1 Introduction

1.1 The problem

We discuss the solution of the following Systems of Differential Equations:

$$\begin{aligned} \left[ \frac{d^{2}}{dx^{2}}+k_{i}^{2}-\frac{l_{i} (l_{i}+1)}{x^{2}}-POTENT_{ii} \right] \delta _{ij} = \sum _{m=1}^{N} POTENT_{im}\,\delta _{mj} \end{aligned}$$
(1)

where \(1 \le i \le N\) and \(m \ne i\).

(3) \(\longrightarrow\) BVP (\(=\) Boundary value problem) \(\longrightarrow\) boundary conditions:

$$\begin{aligned} \delta _{ij}= & {} 0 \hbox { } at \hbox { } x = 0 \end{aligned}$$
(2)
$$\begin{aligned}&\delta _{ij} \sim k_{i}\, x j_{l_{i}}\,(k_{i} x) \theta _{ij} + \left( \frac{k_{i}}{k_{j}} \right) ^{1/2} K_{ij}\, k_{i}\, x\, n_{l{i}}\,(k_{i} x) \end{aligned}$$
(3)

where \(j_{l}(x)\) and \(n_{l}(x)\) \(\longrightarrow\) spherical Bessel and Neumann functions respectively (see [62]).

Categories of problems (see [62]):

  • Open Channels

  • Close Channels

Asymptotic form (4) of (3) for the open channels problem (see [62]) \({\longrightarrow }\):

$$\begin{aligned} \varvec{\delta } \sim \varvec{\Xi } + \mathbf{T} \mathbf{W'}\,. \end{aligned}$$

where:

$$\begin{aligned} W'_{ij}= & {} \left( \frac{k_{i}}{k_{j}} \right) ^{1/2} K_{ij} \\ \Xi _{ij}= & {} k_{i} x j_{l_{i}}(k_{i} x) \theta _{ij} \\ T_{ij}= & {} k_{i} x n_{l_{i}}(k_{i} x) \theta _{ij} \end{aligned}$$

More details see in [67, 143,144,145,146,147,148,149,150,151] and references therein. Areas of application of the problems of the form (1) can also be found in [152,153,154,155,156,157,158,159,160] and references therein (Neural Networks, impulsive delayed systems, delayed switched systems, Impulsive control method, impulsive functional differential equations with infinite delays, singularly perturbed nonlinear systems, etc)

[62] \(\longrightarrow\):

$$\begin{aligned} \left[ \frac{d^{2}}{dx^{2}} + k_{j' j}^{2}-\frac{l' (l' +1)}{x^{2}} \right] \delta _{j' l'}^{Jjl}(x)=\frac{2 \nu }{\hbar ^{2}} \sum _{j''} \sum _{l''} < j' l'; J \mid POTENT \mid j'' l'' ; J > \delta _{j'' l''}^{Jjl}(x) \end{aligned}$$

where (jl), \((j ^\prime ,l ^\prime )\), \(J=j+l=j ^\prime + l ^\prime\) \(\longrightarrow\) [62].

and

$$\begin{aligned} k_{j' j}=\frac{2 \nu }{\hbar ^{2}} \left[ E + \frac{\hbar ^{2}}{2 I} \{ j(j+1)-j' (j' +1) \} \right] . \end{aligned}$$

where for E, I and \(\nu\) \(\longrightarrow\) [62] and references therein.

2 Introductiuon of the algorithm

In this section we will present the development of the new proposed scheme.

$$\begin{aligned} \overline{\{\beta \lambda \}}_{n-1}= & {} \{\beta \lambda \}_{n-1} - a_{0} \, h^2\, \left( \{\eta \sigma \}_{n+1} \right.\nonumber \\&\left.-\, 2 \, \{\eta \sigma \}_{n} + \{\eta \sigma \}_{n-1} \right) - 2\, a_{1} \, h^2\, \{\eta \sigma \}_{n} \nonumber \\ \overline{\overline{\{\beta \lambda \}}}_{n-1}= & {} \{\beta \lambda \}_{n-1} - a_{2} \, h^2\, \left( \{\eta \sigma \}_{n+1} \right.\nonumber \\ &\left.-\, 2 \, \{\eta \sigma \}_{n} + \overline{\{\eta \sigma \}}_{n-1} \right) - 2\, a_{3} \, h^2\, \{\eta \sigma \}_{n} \nonumber \\ \overline{\{\beta \lambda \}}_{n}= & {} \{\beta \lambda \}_{n} - a_{4} \, h^2\, \left( \{\eta \sigma \}_{n+1} - 2 \, \{\eta \sigma \}_{n} + \overline{\overline{\{\eta \sigma \}}}_{n-1} \right) \nonumber \\&\{\beta \lambda \}_{n+1} + a_{5} \, \{\beta \lambda \}_{n} + \{\beta \lambda \}_{n-1} \nonumber \\= & {} h^2 \left( b_{1} \, \left( \{\eta \sigma \}_{n+1} + \{\eta \sigma \}_{n-1} \right) + b_{0} \, \overline{\{\eta \sigma \}}_{n} \right) \end{aligned}$$
(4)

where \(\{\eta \sigma \}_{n+i} = \{\beta \lambda \}''\left( t_{n+i}, \{\beta \lambda \}_{n+i} \right) , i=-1\left( 1 \right) 1\), \(\overline{\{\eta \sigma \}}_{n-1} = \{\beta \lambda \}''\left( t_{n-1}, \overline{\{\beta \lambda \}}_{n-1} \right)\), \(\overline{\overline{\{\eta \sigma \}}}_{n-1} = \{\beta \lambda \}''\left( t_{n-1}, \overline{\overline{\{\beta \lambda \}}}_{n-1} \right)\), \(\overline{\{\eta \sigma \}}_{n} = \{\beta \lambda \}''\left( t_{n}, \overline{\{\beta \lambda \}}_{n} \right)\) and

  • \(b_{{1}} = \frac{1}{12}\),

  • \(a_{{j}}, \, j=0 (1) 5\) and \(b_{0}\), to be determined.

Figure 1\(\longrightarrow\) The Production of the of the new proposed algorithm (more information on flowcharts \(\longrightarrow\) [161]).

Fig. 1
figure 1

Introduction of the new algorithm

In Fig. 1:

The general forms of the stability polynomials \(ST_{k}, \, k=0,\,1\) is presented in [40]

Theorem 1\({\mathop {\longrightarrow }\limits ^{using \, ST_{j}, \, \, j=0,1}}\): \(PhL + DPL_{j}\) (with \(PhL = {\text{phase}}{-}{\text{lag}}\) and \(DPL_{j} = {\text{phase-lag's derivative of order}} j\)

Theorem 1

[12] The terms OPL and \(CF_{PL}\) are defined by:

$$\begin{aligned} -CF_{PL}\, v^{OPL+2} + O\left( v^{OPL+4} \right) = \frac{2\, ST_{1} \left( v \right) \, \cos \left( v \right) +ST_{0} \left( v\right) }{2\, ST_{1} \left( v\right) }. \end{aligned}$$
(8)

where OPL \(\longrightarrow\) phase–lag’s order and \(CF_{PL}\) \(\longrightarrow\) phase–lag’s constant . OPL and \(CF_{PL}\) \({\mathop {\longrightarrow }\limits ^{(4)- (7)}}\) phase–lag.

(4) \(+\) \(ST_{j}, \, \, j=0,1\) with general form given by [40] \(+\) (8) \(+\) Stage 5 of Fig. 1\(\longrightarrow\):

$$\begin{aligned} a_{{0}}= & {} -\frac{1}{3}\,{\frac{PLM_{1}(v)}{{v}^{2} \, PLM_{0}(v)}}, \, a_{{1}} =-\frac{1}{6}\,{\frac{PLM_{2}(v)}{{v}^{2} \, PLM_{0}(v)}}, \nonumber \\ a_{{2}}= & {} -{\frac{PLM_{0}(v)}{{v}^{3}\,PLM_{3}(v)}}, \, a_{{3}} = -\frac{1}{3}\,{\frac{PLM_{4}(v)}{{v}^{3} \, PLM_{3}(v)}}, \nonumber \\ a_{{4}}= & {} -\frac{3}{2}\,{\frac{PLM_{3}(v)}{{v}^{2} \, PLM_{5}(v)}}, \, a_{{5}} = -\frac{1}{12}\,{\frac{PLM_{6}(v)}{PLM_{7}(v)}}, \nonumber \\ b_{{0}}= & {} \frac{1}{6}\,{\frac{PLM_{5}(v)}{v \, PLM_{7}(v)}} \end{aligned}$$
(9)

where

$$\begin{aligned} PLM_{0}(v)= & {} 12700800+743670\,\sin (v) {v}^{5}+1232\, (\cos (v))^{2}{v}^{8}+887\,\sin (v) {v}^{9} (\cos (v))^{2}\\&-\, 1680\,\cos (v) {v}^{7}\sin (v) -529200\,\cos (v) {v}^{3}\sin (v) \\&+\, 371835\,\sin (v) {v}^{5} (\cos (v))^{2}+3628800\,\cos (v) v\sin (v) \\&-\, 453600\,\sin (v) (\cos (v))^{2}v+14\,\sin (v) {v}^{11} (\cos (v))^{2}+27450\,\sin (v) {v}^{7} (\cos (v))^{2}\\&-\, 71280\,\cos (v) {v}^{5}\sin (v) -12436200\,{v}^{2}\\&-\, 189720\,{v}^{6}-200\,\sin (v) \cos (v) {v}^{9}+1025325\,\sin (v) {v}^{3} (\cos (v))^{2}\\&+\, 3432240\,{v}^{4}-12700800\,\cos (v) \\&+\, (\cos (v))^{3}{v}^{12}+44\,\cos (v) {v}^{12}+9261000\,\cos (v) {v}^{2}\\&-\, 601335\,\cos (v) {v}^{6}+191835\,\cos (v) {v}^{4}+2370\,\cos (v) {v}^{10}\\&-\, 11518\,\cos (v) {v}^{8}+1843\, (\cos (v))^{3}{v}^{8}\\&+\, 82440\, (\cos (v))^{3}{v}^{6}+14040\, (\cos (v))^{2}{v}^{6}+1509165\, (\cos (v))^{3}{v}^{4}\\&-\, 143640\, (\cos (v))^{2}{v}^{4}+7068600\, (\cos (v))^{3}{v}^{2}-3893400\, (\cos (v))^{2}{v}^{2}\\&-\, 250950\,\sin (v) {v}^{7}-3175200\,\sin (v) v\\&+\, 864675\,\sin (v) {v}^{3}+35\, (\cos (v))^{3}{v}^{10}\\&-\, 8\, (\cos (v))^{2}{v}^{10}+6828\,\sin (v) {v}^{9}+196\,\sin (v) {v}^{11}\\&+\, 48\,{v}^{10}-1232\,{v}^{8}-12700800\, (\cos (v))^{2}\\&+\, 12700800\, (\cos (v))^{3} \end{aligned}$$
$$\begin{aligned} PLM_{1}(v)= & {} -3175200+13230\,\sin (v) {v}^{5}+192\, (\cos (v))^{2}{v}^{8}\\&+\, 303\,\sin (v) {v}^{9} (\cos (v))^{2}-5760\,\cos (v) {v}^{7}\sin (v)\\&+\, 1360800\,\cos (v) {v}^{3}\sin (v) -186165\,\sin (v) {v}^{5} (\cos (v))^{2}\\&+\, 6350400\,\cos (v) v\sin (v) -7541100\,\sin (v) (\cos (v))^{2}v+6\,\sin (v) {v}^{11} (\cos (v))^{2}\\&+\, 3270\,\sin (v) {v}^{7} (\cos (v))^{2}-30240\,\cos (v) {v}^{5}\sin (v)\\&-\, 3250800\,{v}^{2}-196560\,{v}^{6}-240\,\sin (v) \cos (v) {v}^{9}\\&-\, 1828575\,\sin (v) {v}^{3} (\cos (v))^{2}+2308320\,{v}^{4}+3175200\,\cos (v) + (\cos (v))^{3}{v}^{12}\\&+\, 44\,\cos (v) {v}^{12}+1266300\,\cos (v) {v}^{2}\\&-\, 649215\,\cos (v) {v}^{6}-2218545\,\cos (v) {v}^{4}+3058\,\cos (v) {v}^{10}\\&+\, 24642\,\cos (v) {v}^{8}+4143\, (\cos (v))^{3}{v}^{8}\\&+\, 109620\, (\cos (v))^{3}{v}^{6}-15120\, (\cos (v))^{2}{v}^{6}\\&+\, 725445\, (\cos (v))^{3}{v}^{4}-418320\, (\cos (v))^{2}{v}^{4}+1908900\, (\cos (v))^{3}{v}^{2}\\&+\, 75600\, (\cos (v))^{2}{v}^{2}-229350\,\sin (v) {v}^{7}+1190700\,\sin (v) v+864675\,\sin (v) {v}^{3}\\&+\, 87\, (\cos (v))^{3}{v}^{10}-16\, (\cos (v))^{2}{v}^{10}\\&+\, 972\,\sin (v) {v}^{9}+84\,\sin (v) {v}^{11}+96\,{v}^{10}\\&+\, 2208\,{v}^{8}+3175200\, (\cos (v))^{2}-3175200\, (\cos (v))^{3} \end{aligned}$$
$$\begin{aligned}PLM_{2}(v)= & {} -6350400-524850\,\cos (v) {v}^{7}\sin (v) +2907\,\sin (v) {v}^{9} (\cos (v))^{2}\\&-\, 96948\,\sin (v) \cos (v) {v}^{9}-8745975\,\cos (v) {v}^{3}\sin (v) -295785\,\sin (v) {v}^{5} (\cos (v))^{2}\\&+\, 1587600\,\sin (v) (\cos (v))^{2}v+39690000\,\cos (v) v\sin (v) -22\,\sin (v) {v}^{11} (\cos (v))^{2}\\&-\, 2622375\,\sin (v) {v}^{3} (\cos (v))^{2}+16770\,\sin (v) {v}^{7} (\cos (v))^{2}-1313550\,\cos (v) {v}^{5}\sin (v) \\&-\, 3728025\,\sin (v) {v}^{3} (\cos (v))^{3}+453\,\sin (v) {v}^{9} (\cos (v))^{3}-248535\,\sin (v) {v}^{5} (\cos (v))^{3}\\&-\, 2370\,\sin (v) {v}^{7} (\cos (v))^{3}-1672\,\sin (v) \cos (v) {v}^{11}-14288400\,\sin (v) (\cos (v))^{3}v\\&+\, 22\,\sin (v) {v}^{11} (\cos (v))^{3}+ (\cos (v))^{3}{v}^{12}+44\,\cos (v) {v}^{12}+982800\,\cos (v) {v}^{2}\\&-\, 3608955\,\cos (v) {v}^{6}+11098395\,\cos (v) {v}^{4}\\&+\, 4458\,\cos (v) {v}^{10}+85038\,\cos (v) {v}^{8}\\&+\, 5667\, (\cos (v))^{3}{v}^{8}+245700\, (\cos (v))^{3}{v}^{6}-2401245\, (\cos (v))^{2}{v}^{6}\\&+\, 2434005\, (\cos (v))^{3}{v}^{4}-16268175\, (\cos (v))^{2}{v}^{4}+11718000\, (\cos (v))^{3}{v}^{2}\\&-\, 13381200\, (\cos (v))^{2}{v}^{2}+94650\,\sin (v) {v}^{7}\\&-\, 26989200\,\sin (v) v+15096375\,\sin (v) {v}^{3}\\&+\, 607\, (\cos (v))^{3}{v}^{10}-6384\, (\cos (v))^{2}{v}^{10}\\&-\, 18732\,\sin (v) {v}^{9}-308\,\sin (v) {v}^{11}\\&-\, 1770930\,\sin (v) {v}^{5}+110250\, (\cos (v))^{2}{v}^{8}\\&-\, 129\, (\cos (v))^{4}{v}^{10}-168\, (\cos (v))^{2}{v}^{12}\\&-\, 6621\, (\cos (v))^{4}{v}^{8}-147420\, (\cos (v))^{4}{v}^{6}-1285515\, (\cos (v))^{4}{v}^{4}\\&-\, 2343600\, (\cos (v))^{4}{v}^{2}+ (\cos (v))^{4}{v}^{12}\\&+\, 6350400\, (\cos (v))^{4}-12700800\, (\cos (v))^{3}\\&+\, 28808\,{v}^{10}+325416\,{v}^{8}+4021290\,{v}^{4}+3024000\,{v}^{2}-2706480\,{v}^{6}\\&+\, 392\,{v}^{12}+12700800\,\cos (v) \end{aligned}$$
$$\begin{aligned} PLM_{3}(v)= & {} (\cos (v))^{3}{v}^{11}+22\,\sin (v) (\cos (v))^{2}{v}^{10}\\&-\, 101\, (\cos (v))^{3}{v}^{9}+44\,\cos (v) {v}^{11}\\&+\, 791\,\sin (v) (\cos (v))^{2}{v}^{8}+308\,\sin (v) {v}^{10}\\&-\, 4725\, (\cos (v))^{3}{v}^{7}+2306\,\cos (v) {v}^{9}\\&+\, 23730\,\sin (v) (\cos (v))^{2}{v}^{6}+8764\,\sin (v) {v}^{8}\\&-\, 90720\, (\cos (v))^{3}{v}^{5}+14490\,\cos (v) {v}^{7}\\&+\, 466515\,\sin (v) (\cos (v))^{2}{v}^{4}-561750\,\sin (v) {v}^{6}-826875\, (\cos (v))^{3}{v}^{3}\\&+\, 719145\,\cos (v) {v}^{5}+4729725\,\sin (v) (\cos (v))^{2}{v}^{2}\\&-\, 1954890\,\sin (v) {v}^{4}-793800\, (\cos (v))^{3}v\\&-\, 9492525\,\cos (v) {v}^{3}+5556600\,\sin (v) (\cos (v))^{2}\\&+\, 10352475\,\sin (v) {v}^{2}+793800\,\cos (v) v\\&-\, 5556600\,\sin (v) \end{aligned}$$
$$\begin{aligned} PLM_{4}(v)= & {} 38102400-1351890\,\cos (v) {v}^{7}\sin (v) +2811\,\sin (v) {v}^{9} (\cos (v))^{2}\\&-\, 80124\,\sin (v) \cos (v) {v}^{9}+7130025\,\cos (v) {v}^{3}\sin (v) +987255\,\sin (v) {v}^{5} (\cos (v))^{2}\\&-\, 7484400\,\sin (v) (\cos (v))^{2}v+25174800\,\cos (v) v\sin (v) -14\,\sin (v) {v}^{11} (\cos (v))^{2}\\&-\, 1034775\,\sin (v) {v}^{3} (\cos (v))^{2}+118530\,\sin (v) {v}^{7} (\cos (v))^{2}+3591810\,\cos (v) {v}^{5}\sin (v) \\&+\, 2622375\,\sin (v) {v}^{3} (\cos (v))^{3}+1389\,\sin (v) {v}^{9} (\cos (v))^{3}+587385\,\sin (v) {v}^{5} (\cos (v))^{3}\\&+\, 39870\,\sin (v) {v}^{7} (\cos (v))^{3}-1064\,\sin (v) \cos (v) {v}^{11}-3402000\,\sin (v) (\cos (v))^{3}v\\&+\, 14\,\sin (v) {v}^{11} (\cos (v))^{3}+ (\cos (v))^{3}{v}^{12}\\&+\, 44\,\cos (v) {v}^{12}+58968000\,\cos (v) {v}^{2}\\&-\, 4564755\,\cos (v) {v}^{6}+16105635\,\cos (v) {v}^{4}\\&+\, 2634\,\cos (v) {v}^{10}-47418\,\cos (v) {v}^{8}\\&+\, 21363\, (\cos (v))^{3}{v}^{8}+388260\, (\cos (v))^{3}{v}^{6}-2287845\, (\cos (v))^{2}{v}^{6}\\&+\, 7027965\, (\cos (v))^{3}{v}^{4}-21560175\, (\cos (v))^{2}{v}^{4}+39009600\, (\cos (v))^{3}{v}^{2}\\&-\, 52390800\, (\cos (v))^{2}{v}^{2}+172890\,\sin (v) {v}^{7}\\&-\, 14288400\,\sin (v) v-8717625\,\sin (v) {v}^{3}\\&+\, 591\, (\cos (v))^{3}{v}^{10}-12744\, (\cos (v))^{2}{v}^{10}\\&-\, 12636\,\sin (v) {v}^{9}-196\,\sin (v) {v}^{11}\\&+\, 5719950\,\sin (v) {v}^{5}-224190\, (\cos (v))^{2}{v}^{8}\\&+\, 39\, (\cos (v))^{4}{v}^{10}-168\, (\cos (v))^{2}{v}^{12}\\&-\, 3549\, (\cos (v))^{4}{v}^{8}-157140\, (\cos (v))^{4}{v}^{6}-2429595\, (\cos (v))^{4}{v}^{4}\\&-\, 17803800\, (\cos (v))^{4}{v}^{2}+ (\cos (v))^{4}{v}^{12}-38102400\, (\cos (v))^{4}+76204800\, (\cos (v))^{3}\\&+\, 33240\,{v}^{10}+622344\,{v}^{8}+856170\,{v}^{4}-27783000\,{v}^{2}\\&-\, 182520\,{v}^{6}-76204800\,\cos (v) + 392\,{v}^{12} \end{aligned}$$
$$\begin{aligned} PLM_{5}(v)= & {} 14\, (\cos (v))^{3}{v}^{9}+13936\, (\cos (v))^{2}{v}^{9}\\&-\, 1350\, (\cos (v))^{3}{v}^{7}+307710\, (\cos (v))^{2}{v}^{7}\\&-\, 162540\, (\cos (v))^{3}{v}^{5}+3172365\, (\cos (v))^{2}{v}^{5}-3335850\, (\cos (v))^{3}{v}^{3}\\&-\, 32304825\, (\cos (v))^{2}{v}^{3}-3969000\, (\cos (v))^{3}v+15082200\, (\cos (v))^{2}v\\&-\, 88\,\cos (v) {v}^{11}+21240\,\cos (v) {v}^{7}+568890\,\cos (v) {v}^{5}\\&+\, 23785650\,\cos (v) {v}^{3}-3724\,\cos (v) {v}^{9}\\&-\, 14288400\,\cos (v) \sin (v) +3969000\,\cos (v) v\\&-\, 9525600\,v- (\cos (v))^{4}{v}^{11}+15330\,\sin (v) (\cos (v))^{3}{v}^{6}\\&-\, 1554\,\sin (v) (\cos (v))^{2}{v}^{8}-868770\,\sin (v) (\cos (v))^{2}{v}^{4}-28284\,\cos (v) {v}^{8}\sin (v) \\&-\, 392\,{v}^{11}+14288400\,\sin (v) +45360\,{v}^{5}-365400\,{v}^{7}\\&-\, 152\,\cos (v) {v}^{10}\sin (v) +2\,\sin (v) (\cos (v))^{3}{v}^{10}\\&+\, 339\,\sin (v) (\cos (v))^{3}{v}^{8}-962430\,\cos (v) {v}^{6}\sin (v) +14288400\,\sin (v) (\cos (v))^{3}\\&-\, 14288400\,\sin (v) (\cos (v))^{2}-2\, (\cos (v))^{3}{v}^{11}\\&+\, 168\, (\cos (v))^{2}{v}^{11}-25789050\,\sin (v) {v}^{2}\\&-\, 1566180\,\sin (v) {v}^{4}-336\,\sin (v) {v}^{8}\\&+\, 1267980\,\sin (v) {v}^{6}-135\, (\cos (v))^{4}{v}^{9}\\&-\, 7875\, (\cos (v))^{4}{v}^{7}-448\,\sin (v) {v}^{10}\\&-\, 283500\, (\cos (v))^{4}{v}^{5}-4843125\, (\cos (v))^{4}{v}^{3}\\&-\, 5556600\, (\cos (v))^{4}v+419895\,\sin (v) (\cos (v))^{3}{v}^{4}+12422025\,\sin (v) (\cos (v))^{3}{v}^{2}\\&+\, 26285175\,\cos (v) {v}^{2}\sin (v) -17173170\,\cos (v) {v}^{4}\sin (v) -12918150\,\sin (v) (\cos (v))^{2}{v}^{2}\\&-\, 49980\,\sin (v) (\cos (v))^{2}{v}^{6}-32\,\sin (v) (\cos (v))^{2}{v}^{10}-28616\,{v}^{9}+16698150\,{v}^{3} \end{aligned}$$
$$\begin{aligned} PLM_{6}(v)= & {} - (\cos (v))^{4}{v}^{12}- (\cos (v))^{3}{v}^{12}\\&+\, 44898\,\cos (v) {v}^{8}+513675\,\cos (v) {v}^{6}\\&+\, 9205245\,\cos (v) {v}^{4}-20752200\,\cos (v) {v}^{2}\\&-\, 906\,\cos (v) {v}^{10}+19051200\,\cos (v) -19051200\, (\cos (v))^{3}\\&-\, 44\,\cos (v) {v}^{12}+1053\, (\cos (v))^{4}{v}^{8}\\&-\, 2523\, (\cos (v))^{3}{v}^{8}+61020\, (\cos (v))^{4}{v}^{6}\\&-\, 95580\, (\cos (v))^{3}{v}^{6}+1295595\, (\cos (v))^{4}{v}^{4}-2787075\, (\cos (v))^{2}{v}^{6}\\&-\, 1607445\, (\cos (v))^{3}{v}^{4}+17917200\, (\cos (v))^{4}{v}^{2}-27972945\, (\cos (v))^{2}{v}^{4}\\&-\, 18257400\, (\cos (v))^{3}{v}^{2}+30618000\, (\cos (v))^{2}{v}^{2}+463590\,\sin (v) {v}^{7}\\&+\, 15082200\,\sin (v) v-25453575\,\sin (v) {v}^{3}\\&-\, 63\, (\cos (v))^{4}{v}^{10}+168\, (\cos (v))^{2}{v}^{12}\\&-\, 39\, (\cos (v))^{3}{v}^{10}+8784\, (\cos (v))^{2}{v}^{10}\\&+\, 6348\,\sin (v) {v}^{9}-140\,\sin (v) {v}^{11}\\&-\, 6086430\,\sin (v) {v}^{5}-111498\, (\cos (v))^{2}{v}^{8}+210105\,\sin (v) {v}^{5} (\cos (v))^{2}\\&-\, 26989200\,\cos (v) v\sin (v) -10\,\sin (v) {v}^{11} (\cos (v))^{2}\\&-\, 760\,\cos (v) \sin (v) {v}^{11}+1083\,\sin (v) {v}^{9} (\cos (v))^{3}\\&+\, 621495\,\sin (v) {v}^{5} (\cos (v))^{3}+6600825\,\sin (v) {v}^{3} (\cos (v))^{3}-392\,{v}^{12}+3177360\,{v}^{6}\\&+\, 7030800\,\sin (v) (\cos (v))^{3}v-622350\,\cos (v) {v}^{7}\sin (v) +39741975\,\cos (v) {v}^{3}\sin (v) \\&-\, 363\,\sin (v) {v}^{9} (\cos (v))^{2}-65388\,\cos (v) \sin (v) {v}^{9}\\&+\, 32130\,\sin (v) {v}^{7} (\cos (v))^{3}+15110550\,{v}^{4}\\&-\, 19051200\, (\cos (v))^{2}-19656\,{v}^{10}+200280\,{v}^{8}\\&-\, 2970\,\sin (v) {v}^{7} (\cos (v))^{2}-2153970\,\cos (v) {v}^{5}\sin (v) \\&+\, 4876200\,\sin (v) (\cos (v))^{2}v+10\,\sin (v) {v}^{11} (\cos (v))^{3}\\&-\, 9525600\,{v}^{2}+19051200\, (\cos (v))^{4}+4172175\,\sin (v) {v}^{3} (\cos (v))^{2} \end{aligned}$$
$$\begin{aligned} PLM_{7}(v)= & {} 793800+2338\,\cos (v) {v}^{8}-6030\,\cos (v) {v}^{6}\\&-\, 36855\,\cos (v) {v}^{4}+902475\,\cos (v) {v}^{2}\\&+\, 44\,\cos (v) {v}^{10}-793800\,\cos (v) +793800\, (\cos (v))^{3}\\&-\, 333\, (\cos (v))^{3}{v}^{8}-2925\, (\cos (v))^{3}{v}^{6}\\&-\, 6480\, (\cos (v))^{2}{v}^{6}+22680\, (\cos (v))^{3}{v}^{4}\\&+\, 279720\, (\cos (v))^{2}{v}^{4}+722925\, (\cos (v))^{3}{v}^{2}-340200\, (\cos (v))^{2}{v}^{2}\\&+\, 28620\,\sin (v) {v}^{7}-496125\,\sin (v) v\\&+\, 746550\,\sin (v) {v}^{3}+ (\cos (v))^{3}{v}^{10}+420\,\sin (v) {v}^{9}\\&+\, 236250\,\sin (v) {v}^{5}+8\, (\cos (v))^{2}{v}^{8}\\&-\, 32550\,\sin (v) {v}^{5} (\cos (v))^{2}+831600\,\cos (v) v\sin (v) \\&-\, 5040\,{v}^{6}+360\,\cos (v) {v}^{7}\sin (v) +630000\,\cos (v) {v}^{3}\sin (v) \\&+\, 30\,\sin (v) {v}^{9} (\cos (v))^{2}-430920\,{v}^{4}\\&-\, 793800\, (\cos (v))^{2}-48\,{v}^{8}-1305\,\sin (v) {v}^{7} (\cos (v))^{2}\\&-\, 58800\,\cos (v) {v}^{5}\sin (v) -335475\,\sin (v) (\cos (v))^{2}v\\&-\, 332325\,\sin (v) {v}^{3} (\cos (v))^{2}-1285200\,{v}^{2} \end{aligned}$$

where \(PLM_{j}, \, \, j=0 \left( 1 \right) 7\) are the Polynomials of the Stability Functions of the Finite Difference Method. \(v \rightarrow 0 \, \bigvee \, PLM_{0} (v) \rightarrow 0 \bigvee \, PLM_{3} (v)\bigvee \, PLM_{5} (v) \rightarrow 0\bigvee \, PLM_{7} (v) \rightarrow 0\) \(\Longrightarrow\) expressions in Taylor series are procured:

$$\begin{aligned} a_{{0}}= & {} {\frac{6253}{844920}}+{\frac{3593135\,{v}^{2}}{13087979784}}+{\frac{155059456088527\,{v}^{4}}{14475309305738339520}}\nonumber \\&+\, {\frac{139425749259805708667053\,{v}^{6}}{332302096459882575766067328000}}+{\frac{12067246301799966527661025273\,{v}^{8}}{735052423458434275128783358533703680}}\nonumber \\&+\, {\frac{1260798970420267150992698787831456433\,{v}^{10}}{1964103811100132159983479296611888988328960000}}\nonumber \\&+\, {\frac{26931431246550687596648993340213858136431772243\,{v}^{12}}{1073115886322751758827494051328914422575848767101747200000}}\nonumber \\&+\, {\frac{97863671907202032375649481164664464470467236177873\,{v}^{14}}{99736678213900135767537890123370901131506475432956906864640000}}\nonumber \\&+\, {\frac{306830976068054013982599580863755706218398825647326804187343\,{v}^{16}}{7997387567236150128692781800561665211659139702173100865966367752192000000}}\nonumber \\&+\, \cdots \nonumber \\ a_{{1}}= & {} {\frac{9985}{14082}}-{\frac{28335125\,{v}^{2}}{1090664982}} +{\frac{203351534695147\,{v}^{4}}{241255155095638992}}\nonumber \\&-\, {\frac{27365377075618775531531\,{v}^{6}}{5538368274331376262767788800}} +{\frac{185855534073392276501922089063\,{v}^{8}}{612543686215361895940652798778086400}}\nonumber \\&+\, {\frac{37343460375933113598915017735122133\,{v}^{10}}{5036163618205467076880716145158689713664000}}\nonumber \\&+\, {\frac{5717010091236424020246422687686736347446346429\,{v}^{12}}{17885264772045862647124900855481907042930812785029120000}}\nonumber \\&+\, {\frac{12088619343930757998993122077959436749388380738011\,{v}^{14}}{977810570724511134975861667876185305210847798362322616320000}}\nonumber \\&+\, {\frac{129046489352538208519866214761253483454606765098381992672671\, {v}^{16}}{266579585574538337623092726685388840388637990072436695532212258406400000}}\nonumber \\&+\, \cdots \nonumber \\ a_{{2}}= & {} {\frac{2347}{173838}}+{\frac{706225\,{v}^{2}}{3392001558}} -{\frac{334471512575\,{v}^{4}}{842032719046954512}}\nonumber \\&-\, {\frac{7841623911295416464221\,{v}^{6}}{34089178296152633825813241600}} -{\frac{388086864125437095759628783\,{v}^{8}}{30222572340897565950959783695630080}}\nonumber \\&-\, {\frac{28696155154708289802564386864574089\,{v}^{10}}{56966544738901226599503666863763355170048000}}\nonumber \\&-\, {\frac{2372654593188563133854814744533991444773\,{v}^{12}}{149936855437299327738855912009605381528644207704000}}\nonumber \\&-\, {\frac{1643852457078370958422039614125061421413837943\,{v}^{14}}{4172787386362575557678066341577575651930196268455098368000}}\nonumber \\&-\, {\frac{1693438691000777535139766424322495017635497116807939871\,{v}^{16}}{262848336048573088926499022293076802538891393845397527788375224320000}}\nonumber \\&+\, {\frac{1284885800635756729106743771603107104181991930827236184217049\, {v}^{18}}{39038918922619090192343985661346398972644111027275100633987960339897876480000}}\nonumber \\&+\, \cdots \nonumber \\ a_{{3}}= & {} -{\frac{2149}{4139}}+{\frac{120575\,{v}^{2}}{17131321}} - {\frac{9105133539\,{v}^{4}}{67503023813288}}\nonumber \\&-\, {\frac{22798808971401383\,{v}^{6}}{14014453980650063445120}} + {\frac{284523356025137766286747\,{v}^{8}}{3727454316165015965634338956800}}\nonumber \\&+\, {\frac{380135844902730132032323513117\,{v}^{10}}{140517617540240565852674897605513881600}}\nonumber \\&+\, {\frac{24326982349154601537014420718636655849\,{v}^{12}}{192319198893441497821203671007991510698918336000}}\nonumber \\&+\, {\frac{20443381161218553287797991636756091101472479\,{v}^{14}}{5043514064497630821677711195897959002591966481772544000}}\nonumber \\&+\, {\frac{36116648956084847324390538204882996927562464153653\,{v}^{16}}{341242040673521525812068402413800367973665572692930886901760000}}\nonumber \\&+\, {\frac{300378001915884159863531799872583445903386549623805754807 \,{v}^{18}}{156481156495988015842327984853881669763684908719236414277649352011776000}} + \cdots \nonumber \\ a_{{4}}= & {} {\frac{4139}{1687400}}+{\frac{371\,{v}^{2}}{21902452}} -{\frac{913246049\,{v}^{4}}{4398025503071200}}\nonumber \\&-\, {\frac{98800064047693\,{v}^{6}}{13015692594809032128000}} +{\frac{54680106678648213863\,{v}^{8}}{415094646036686379361678080000}}\nonumber \\&+\, {\frac{249723269616349922681329\,{v}^{10}}{13121190595883896061784921953280000}}\nonumber \\&+\, {\frac{37634958285389933821373122383709\,{v}^{12}}{40311567048828011051023955807328478310400000}}\nonumber \\&+\, {\frac{11837158039143071446902882008083\,{v}^{14}}{459882545180086743259826027091026644162200000}}\nonumber \\&+\, {\frac{14784751989266194391946190194110556000523901\,{v}^{16}}{27583989318919433090894410135787926782401793810063360000000}}\nonumber \\&+\, {\frac{28881315212763976201711723501011223761848516633\,{v}^{18}}{3995728423972848535361073390157804552333020165585586126848000000}} + \cdots \nonumber \\ a_{{5}}= & {} -2-{\frac{53\,{v}^{16}}{96992075980800}}-{\frac{3605821607 \,{v}^{18}}{153374028035998049280000}} + \cdots \nonumber \\\ b_{{0}}= & {} \frac{5}{6}+{\frac{53\,{v}^{14}}{24248018995200}} +{\frac{17399693419\,{v}^{16}}{175284603469712056320000}}\nonumber \\&+\, {\frac{382402324300573\,{v}^{18}}{108936296047404976070688768000}} + \cdots \end{aligned}$$
(10)

\(a_{{j}}, \, j=0 (1)5\) and \(b_{{0}}\), for \(v = \phi \, h\) \({\mathop {\longrightarrow }\limits ^{\text{are plotted in}}}\) Fig. 2

Fig. 2
figure 2

Forms of \(a_{{j}}, \, j=0 \left( 1 \right) 4\) and \(b_{0}\)

LTE \({\mathop {\longrightarrow }\limits ^{for \, the\, Method \, (4), \, which \, is \, declared \, as \, NM142S4SPD6}}\):

$$\begin{aligned} LTE_{NM142S4SPD6}= & {} \frac{53}{96992075980800}\, h^{16} \, \left(3\, \{\beta \lambda \}_{n}^{(16)} + 20 \, \phi ^{2} \, \{\beta \lambda \}_{n}^{(14)} \right.\nonumber \\&+\, 56 \, \phi ^{4} \, \{\beta \lambda \}_{n}^{(12)} + 84 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} + 70 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} \nonumber \\&\left.+\, 28\, \phi ^{10} \, \{\beta \lambda \}_{n}^{(6)} - 4\, \phi ^{14} \, \{\beta \lambda \}_{n}^{(2)} - \phi ^{16} \, \{\beta \lambda \}_{n} \right) + O \left( h^{18} \right) . \end{aligned}$$
(11)

3 Theoretical study of the new proposed method

3.1 Theoretical study of the local truncation error of the new proposed method

Local Truncation Error of the Finite Difference Method \({\mathop {\longrightarrow }\limits ^{scalar \, pattern}}\):

$$\begin{aligned} \{\beta \lambda \}''(x)= & {} \left( POTENT(x)-POTENT_{z} + \imath \right) \, \{\beta \lambda \}(x) \end{aligned}$$
(12)

with

  • POTENT(x) \(\longrightarrow\) the potential.

  • \(POTENT_{z}\) \(\longrightarrow\) POTENT(x) on \(x_{z}\).

  • \(\hbox {PTN}(x) = POTENT(x) - POTENT_{z}\),

  • \(\imath =POTENT_{z}-E\) and

  • E \(\longrightarrow\) the energy.

For the contemplation of the Local Truncation Error of the Finite Difference Method, we use:

3.1.1 Classical algorithm, related as method A

$$\begin{aligned} LTE_{CL} = \frac{53}{32330691993600}\, h^{16} \, \{\beta \lambda \}_{n}^{(16)} + O \left( h^{18} \right) . \end{aligned}$$
(13)

3.1.2 Procedure projected in [40], related as method B

$$\begin{aligned} LTE_{NM142S4SPD1}= & {} \frac{53}{32330691993600}\, h^{16} \, \left( \{\beta \lambda \}_{n}^{(16)} + 4 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} \right.\nonumber \\&\left.+\, 3 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} \right) + O \left( h^{18} \right) . \end{aligned}$$
(14)

3.1.3 Procedure projected in [41], related as method C

$$\begin{aligned} LTE_{NM142S4SPD2}= & {} - \frac{53}{32330691993600}\, h^{16} \, \left(\{\beta \lambda \}_{n}^{(16)} - 6 \, \phi ^{4} \, \{\beta \lambda \}_{n}^{(12)} \right.\nonumber \\&\left.-\, 8 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} - 3 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} \right) + O \left( h^{18} \right) + O \left( h^{18} \right) . \end{aligned}$$
(15)

3.1.4 Procedure projected in [42], related as Method D

$$\begin{aligned} LTE_{NM142S4SPD3}= & {} - \frac{53}{32330691993600}\, h^{16} \, \left(\{\beta \lambda \}_{n}^{(16)} - 10 \, \phi ^{4} \, \{\beta \lambda \}_{n}^{(12)} \right.\nonumber \\&\left.-\, 20 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} - 15 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} - 4 \, \phi ^{10} \, \{\beta \lambda \}_{n}^{(6)} \right) + O \left( h^{18} \right) . \end{aligned}$$
(16)

3.1.5 Procedure projected in [43], related as Method E

$$\begin{aligned} LTE_{NM142S4SPD4}= & {} \frac{53}{32330691993600}\, h^{16} \, \left(\{\beta \lambda \}_{n}^{(16)} + 5 \, \phi ^{2} \, \{\beta \lambda \}_{n}^{(14)} \right.\nonumber \\&\left.+\, 10 \, \phi ^{4} \, \{\beta \lambda \}_{n}^{(12)} + 10 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} + 5 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} + \phi ^{10} \, \{\beta \lambda \}_{n}^{(6)} \right) + O \left( h^{18} \right) . \end{aligned}$$
(17)

3.1.6 Procedure projected in in [44], Related as Method F

$$\begin{aligned} LTE_{NM142S4SPD5}= & {} \frac{53}{193984151961600}\, h^{16} \, \left(6\, \{\beta \lambda \}_{n}^{(16)} + 35 \, \phi ^{2} \, \{\beta \lambda \}_{n}^{(14)} \right.\nonumber \\&+\, 84 \, \phi ^{4} \, \{\beta \lambda \}_{n}^{(12)} + 105 \, \phi ^{6} \, \{\beta \lambda \}_{n}^{(10)} + 70 \, \phi ^{8} \, \{\beta \lambda \}_{n}^{(8)} \nonumber \\&\left.+\, 21\, \phi ^{10} \, \{\beta \lambda \}_{n}^{(6)} + \phi ^{14} \, \{\beta \lambda \}_{n}^{(2)} \right) + O \left( h^{18} \right) . \end{aligned}$$
(18)

3.1.7 Procedure projected in Section 2, Related as Method G

The LTE of Method G is given by (11).

Figure 3\(\longrightarrow\) flowchart for Local Truncation Error of the Finite Difference Method.

Fig. 3
figure 3

Investigation of the local truncation error of the new introduced method

Stage 4.1 \(\longrightarrow\):

  • \(\imath \approx 0 \, \equiv \, E \approx V\): \(POTENT_{z} \approx E \Rightarrow \imath =POTENT_{z} - E \approx 0 \Rightarrow \imath ^{i} \approx 0, \, i=1,2, \ldots \Rightarrow h^{\rho } \, \sum \limits _{i=0}^{\zeta }{\ell _{i}\, \imath ^{i}} \approx h^{\rho } \, \ell _{0}\).

Physical Causality:

$$\begin{aligned} LTE_{CL}= & {} LTE_{NM142S4SPD1}=LTE_{NM142S4SPD2}=\nonumber \\ LTE_{NM142S4SPD3}= & {} LTE_{NM142S4SPD4}=\nonumber \\ LTE_{NM142S4SPD5}= & {} LTE_{NM142S4SPD6} \approx h^{16} \, \ell _{0} \end{aligned}$$
(20)

\(\ell _{0}\) \(\longrightarrow\) Supplement Material A.

Conclusion 1

\(\imath \approx 0\) \(\longrightarrow\) \(LTE_{CL}=LTE_{NM142S4SPD1}=LTE_{NM142S4SPD2}=LTE_{NM142S4SPD3} =LTE_{NM142S4SPD4}=LTE_{NM142S4SPD5}\).

Stage 4.2 \(\longrightarrow\):

  • \(\left| \imath \right|>>0\) \(\equiv\) \(\left| V \right|>> \bigvee<< \left| E \right|\): \(E<<POTENT_{z} \vee E>>POTENT_{z} \Rightarrow \imath =POTENT_{z} - E>>0 \vee \imath =POTENT_{z} - E<<0\).

Conclusion 2

\(\left| \imath \right|>>0\) \(\longrightarrow\) \(\min {LTE}=\sum \limits _{i=0}^{\daleth }{\ell _{i}\, \imath ^{i}}\) and \(\daleth \longrightarrow \min {}\).

Physical Causality: Asymptotic forms of LTEs:

3.1.8 Method A

$$\begin{aligned} LTE_{CL} = \frac{53}{32330691993600}\, h^{16} \,\left( \{\beta \lambda \} (x) \, \imath ^{8} + \cdots \right) + O \left( h^{18} \right) . \end{aligned}$$
(21)

3.1.9 Method B

$$\begin{aligned} LTE_{NM142S4SPD1}= & {} \frac{53}{16165345996800}\, h^{16} \, \left[\nonumber \right.\\&\left( 6\, \left( {\frac{\mathrm{d}}{\mathrm{d}{x}}}{\text{PTN}} (x) \right) \, \left( \frac{{\mathrm{d}}}{{\mathrm{d}}{x}}\{\beta \lambda \} (x) \right) + 59\, \left( {\frac{{\mathrm{d}}^{2}}{{\mathrm{d}}{x}^{2}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x)\right. \nonumber \\&\left.\left.+\, 3\, {\text{PTN}} (x)^{2}\, \{\beta \lambda \} (x)\right) \imath ^{6} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(22)

3.1.10 Method C

$$\begin{aligned} LTE_{NM142S4SPD2}= & {} \frac{53}{2020668249600}\, h^{16} \nonumber \\&\left[ \left(\left( {\frac{{\mathrm{d}}^{2}}{{{\mathrm{d}}}{x}^{2}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \right) \imath ^{6} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(23)

3.1.11 Method D

$$\begin{aligned} LTE_{NM142S4SPD3}= & {} \frac{53}{8082672998400}\, h^{16} \nonumber \\&\left[ \left(10\, \left( {\frac{{\mathrm{d}}{^{3}}}{{\mathrm{d}}{x}^{3}}}{\text{PTN}} (x) \right) \, \left( \frac{\mathrm{d}}{{\mathrm{d}}{x}}\{\beta \lambda \} (x) \right) \right.\right.\nonumber \\&+\, 20\, \left( {\frac{{\mathrm{d}}^{2}}{{\mathrm{d}}{x}^{2}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \, {\text{PTN}} (x) \nonumber \\&+\, 79\, \left( {\frac{{\mathrm{d}}^{4}}{{\mathrm{d}}{x}^{4}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \nonumber \\&+\left.\left.\, 15\, \left( {\frac{\mathrm{d}}{{\mathrm{d}}{x}}}{\text{PTN}} (x) \right)^2\, \{\beta \lambda \} (x) \right) \imath ^{5} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(24)

3.1.12 Method E

$$\begin{aligned} LTE_{NM142S4SPD4}= & {} \frac{53}{2020668249600}\, h^{16} \nonumber \\&\left[ \left(\left( {\frac{{\mathrm{d}}^{4}}{{\mathrm{d}}{x}^{4}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \right) \imath ^{5} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(25)

3.1.13 Method F

$$\begin{aligned} LTE_{NM142S4SPD5}= & {} \frac{1537}{351596275430400}\, h^{16} \nonumber \\ &\left[ \left(87\, \left( {\frac{{\mathrm{d}}^{6}}{{\mathrm{d}}{x}^{6}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \right.\right.\nonumber \\&+\, 14\, \left( {\frac{{\mathrm{d}}{^{5}}}{{{\mathrm{d}}}{x}^{5}}}{\text{PTN}} (x) \right) \, \left( \frac{{{\mathrm{d}}}}{{{\mathrm{d}}}{x}}\{\beta \lambda \} (x) \right) \nonumber \\&+\, 70\, \left( {\frac{{{\mathrm{d}}}^{2}}{{{\mathrm{d}}}{x}^{2}}}{\text{PTN}} (x) \right)^2\, \{\beta \lambda \} (x) \nonumber \\&+\, 105\, \left( {\frac{{{\mathrm{d}}}^{3}}{{{\mathrm{d}}}{x}^{3}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \, \left( {\frac{{{\mathrm{d}}}}{{{\mathrm{d}}}{x}}}{\text{PTN}} (x) \right) \nonumber \\&\left.\left.+\, 42\, \left( {\frac{{{\mathrm{d}}}^{4}}{{{\mathrm{d}}}{x}^{4}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \, {\text{PTN}} (x) \right) \imath ^{4} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(26)

3.1.14 Method G

$$\begin{aligned} LTE_{NM142S4SPD6}= & {} \frac{53}{378875296800}\, h^{16} \nonumber \\&\left[\left ( \left( {\frac{{\mathrm{d}}^{6}}{{\mathrm{d}}{x}^{6}}}{\text{PTN}} (x) \right) \, \{\beta \lambda \} (x) \right) \, \imath^{4} + \cdots \right] + O \left( h^{18} \right) . \end{aligned}$$
(27)

The above theoretical results give:

Theorem 2

  • Method A: \(LTE=O\left( \imath ^8 \right)\).

  • Method B: \(LTE=ADSX\,\, \, O\left( \imath ^6 \right)\).

  • Method C: \(LTE=BYSP\,\, \, O\left( \imath ^6 \right)\).

  • Method D: \(LTE=TNSI\,\, \, O\left( \imath ^5 \right)\).

  • Method E: \(LTE=VCSM\,\, \, O\left( \imath ^5 \right)\).

  • Method F: \(LTE=STVY\,\, \, O\left( \imath ^4 \right)\).

  • Method F: \(LTE=AZCC\,\, \, O\left( \imath ^4 \right)\).

with \({\text{BYSP}}<< {\text{ADSX}}\), \({\text{VCSM}}<< {\text{TNSI}}\) and \({\text{AZCC}}<< {\text{STVY}}\). Theorem 2\(\longrightarrow\) Method G is the most effectual one on accuracy.

3.2 Theoretical study of the stability (stability analysis of the new introduced method

Stability Analysis of the Finite Difference Method \({\mathop {\longrightarrow }\limits ^{{\text{for}} \, {\text{the}} \, {\text{newly}} \, {\text{Produced}} \, {\text{Scheme}}}}\) scholar’s paragon:

$$\begin{aligned} \{\beta \lambda \}''=-\chi ^{2} \, \{\beta \lambda \}\,. \end{aligned}$$
(28)

Conclusion 3

(5), (28) \(\longrightarrow\) \(\chi \ne \phi\).

Figure 4\(\longrightarrow\) Stability Analysis of the New Introduced Finite Difference Method.

Fig. 4
figure 4

Stability analysis of the new introduced method

Stage 1 \(+\) Stage 2 \(\longrightarrow\):

$$\begin{aligned} ST_{1} \left( s,v\right) \, \left( \{\beta \lambda \}_{n+1} + \{\beta \lambda \}_{n-1} \right) + ST_{0} \left( s,v\right) \, \{\beta \lambda \}_{n} = 0 \end{aligned}$$
(29)

and

$$\begin{aligned} ST_{1} \left( s,v\right) \, \left( \sigma ^2 + 1 \right) + ST_{0} \left( s,v\right) \, \sigma = 0 \end{aligned}$$
(30)

where \(ST_{j} \left( s,v\right) , \, j=0,1\) are given in [40]

Stage 3 \(\longrightarrow\): \(s = \chi \, h\) \(\wedge\) \(v = \phi \, h\).

Stage 4 \(\longrightarrow\):

$$\begin{aligned} ST_{1} \left( s,v\right) = {\frac{PLM_{9}\left( s,v \right) }{PLM_{8}\left( s,v \right) }}, \, ST_{0} \left( s,v\right) = \frac{1}{2} \, {\frac{PLM_{10}\left( s,v \right) }{PLM_{8}\left( s,v \right) }} \end{aligned}$$
(31)

where

$$\begin{aligned} PLM_{8}\left( s,v \right)= & {} -3987900\,{v}^{11}\sin (3\,v)-27839700\,\sin (v) {v}^{9} \\&-\, 13970880\,{v}^{12}+272160\,{v}^{12}\cos (3\,v) -1411200\,{v}^{13}\sin (2\,v) +15120000\,{v}^{11}\sin (2\,v) \\&-\, 952560\,\cos (v) {v}^{12}+69344100\,\cos (v) {v}^{10}-9525600\,\cos (v) {v}^{8}\\&+\, 31846500\,\sin (v) {v}^{11}-69854400\,{v}^{10}+19051200\,{v}^{8}+19958400\,{v}^{9}\sin (2\,v) \\&-\, 19051200\,{v}^{8}\cos (2\,v) +8640\,{v}^{15}\sin (2\,v) \\&-\, 155520\,{v}^{14}\cos (2\,v) +6713280\,{v}^{12}\cos (2\,v) \\&-\, 35100\,{v}^{14}\cos (3\,v) -8164800\,{v}^{10}\cos (2\,v) \\&+\, 360\,{v}^{17}\sin (3\,v) -390600\,{v}^{13}\sin (3\,v) \\&+\, 12\,{v}^{18}\cos (3\,v) +192\,{v}^{16}\cos (2\,v) \\&-\, 3996\,{v}^{16}\cos (3\,v) -4025700\,{v}^{9}\sin (3\,v) +100236\,\cos (v) {v}^{16}\\&-\, 394740\,\cos (v) {v}^{14}+1358100\,\sin (v) {v}^{15}+8675100\,{v}^{10}\cos (3\,v) -397440\,{v}^{14}\\&+\, 10949400\,\sin (v) {v}^{13}-15660\,{v}^{15}\sin (3\,v) \\&+\, 20520\,\sin (v) {v}^{17}+2148\,\cos (v) {v}^{18}\\&+\, 9525600\,{v}^{8}\cos (3\,v) -2112\,{v}^{16}\\ PLM_{9}\left( s,v \right)= & {} 537\,\cos (v) {s}^{6}{v}^{14}-3987900\,{v}^{11}\sin (3\,v) \\&-\, 13970880\,{v}^{12}+272160\,{v}^{12}\cos (3\,v) \\&-\, 2381400\,\cos (v) {s}^{4}{v}^{6}-12493\,\cos (v) {s}^{8}{v}^{10}\\&-\, 26763\,\cos (v) {s}^{4}{v}^{14}+6697845\,\cos (v) {s}^{8}{v}^{4}\\&-\, 793800\,\cos (v) {s}^{2}{v}^{8}-110997\,\cos (v) {s}^{8}{v}^{8}\\&-\, 1411200\,{v}^{13}\sin (2\,v) +15120000\,{v}^{11}\sin (2\,v) \\&-\, 131355\,\cos (v) {s}^{4}{v}^{12}-121629\,\cos (v) {s}^{6}{v}^{10}\\&-\, 952560\,\cos (v) {v}^{12}+69344100\,\cos (v) {v}^{10}\\&-\, 39463200\,\sin (v) {s}^{6}{v}^{3}-107541\,\sin (v) {s}^{4}{v}^{13}\\&+\, 113175\,\sin (v) {s}^{2}{v}^{15}-2929050\,\sin (v) {s}^{6}{v}^{9}\\&-\, 9525600\,\cos (v) {v}^{8}-27839700\,\sin (v) {v}^{9}\\&+\, 31846500\,\sin (v) {v}^{11}+2268000\,\cos (v) {s}^{8}{v}^{6}\\&+\, 174749400\,\cos (v) {s}^{6}{v}^{4}-10791900\,\cos (v) {s}^{8}{v}^{2}\\&-\, 69854400\,{v}^{10}+19051200\,{v}^{8}\\&+\, 19958400\,{v}^{9}\sin (2\,v) -19051200\,{v}^{8}\cos (2\,v) \\&+\, 84597\,\sin (v) {s}^{6}{v}^{11}-79380\,\cos (v) {s}^{2}{v}^{12}\\&+\, 8640\,{v}^{15}\sin (2\,v) +2778300\,\sin (v) {s}^{8}v\\&+\, 914130\,\sin (v) {s}^{8}{v}^{7}-3762\,\sin (v) {s}^{4}{v}^{15}\\&+\, 1710\,\sin (v) {s}^{2}{v}^{17}+3175200\,{s}^{8}\cos (3\,v) \\&-\, 6350400\,{s}^{8}\cos (2\,v) -155520\,{v}^{14}\cos (2\,v) \\&-\, 151200\,{s}^{8}{v}^{2}\cos (2\,v) -{v}^{12}{s}^{8}\cos (3\,v) \\&+\, 133245\,\sin (v) {s}^{8}{v}^{5}+60480\,{s}^{8}{v}^{5}\sin (2\,v) \\&+\, 6713280\,{v}^{12}\cos (2\,v) +3\,{v}^{14}{s}^{6}\cos (3\,v) \\&-\, 3\,{s}^{4}{v}^{16}\cos (3\,v) +{v}^{18}{s}^{2}\cos (3\,v) -87\,{s}^{8}{v}^{10}\cos (3\,v) \\&-\, 35100\,{v}^{14}\cos (3\,v) +21205800\,{s}^{6}{v}^{4}\cos (3\,v) \\&-\, 14189175\,{s}^{4}{v}^{7}\sin (3\,v) +1587600\,{s}^{2}{v}^{8}\\&+\, 50009400\,\sin (v) {s}^{4}{v}^{5}-8164800\,{v}^{10}\cos (2\,v) \\&+\, 21772800\,{s}^{6}{v}^{3}\sin (2\,v) -32895\,\cos (v) {s}^{2}{v}^{14}\\&-\, 2925\,{s}^{2}{v}^{14}\cos (3\,v) +186165\,{s}^{8}{v}^{5}\sin (3\,v) \\&+\, 14175\,{s}^{4}{v}^{12}\cos (3\,v) -384\,{s}^{8}{v}^{8}\cos (2\,v) \\&+\, 5778675\,\cos (v) {s}^{2}{v}^{10}+5529\,{s}^{6}{v}^{10}\cos (3\,v) \\&-\, 16669800\,{s}^{4}{v}^{5}\sin (3\,v) -4143\,{s}^{8}{v}^{8}\cos (3\,v) \\&+\, 360\,{v}^{17}\sin (3\,v) +38102400\,{s}^{6}{v}^{2}\cos (3\,v) \\&+\, 2661\,{s}^{6}{v}^{11}\sin (3\,v) +16\,{s}^{2}{v}^{16}\cos (2\,v) \\&-\, 5821200\,{s}^{2}{v}^{10}-1908900\,{s}^{8}{v}^{2}\cos (3\,v) \\&+\, 1260000\,{s}^{2}{v}^{11}\sin (2\,v) -390600\,{v}^{13}\sin (3\,v) \\&-\, 48\,{s}^{6}{v}^{12}\cos (2\,v) -12700800\,{s}^{8}v\sin (2\,v) \\&-\, 66\,{s}^{4}{v}^{15}\sin (3\,v) -76204800\,{s}^{6}{v}^{2}\cos (2\,v) \\&+\, 32\,{s}^{8}{v}^{10}\cos (2\,v) +2480625\,{s}^{4}{v}^{8}\cos (3\,v) \\&-\, 1360800\,{s}^{6}{v}^{3}\sin (3\,v) -333\,{s}^{2}{v}^{16}\cos (3\,v) \\&+\, 303\,{s}^{4}{v}^{14}\cos (3\,v) +105\,{s}^{6}{v}^{12}\cos (3\,v) \\&+\, 12\,{v}^{18}\cos (3\,v) +192\,{v}^{16}\cos (2\,v) -3996\,{v}^{16}\cos (3\,v) \\&-\, 7392\,{s}^{6}{v}^{10}+720\,{s}^{2}{v}^{15}\sin (2\,v) -4025700\,{v}^{9}\sin (3\,v) \\&+\, 7541100\,{s}^{8}v\sin (3\,v) +722925\,{s}^{2}{v}^{10}\cos (3\,v) \\&+\, 100236\,\cos (v) {v}^{16}-9216\,{s}^{8}{v}^{8}\\&-\, 10080\,{s}^{6}{v}^{9}\sin (2\,v) -1587600\,{s}^{2}{v}^{8}\cos (2\,v) \\&+\, 42\,{s}^{6}{v}^{13}\sin (3\,v) -3270\,{s}^{8}{v}^{7}\sin (3\,v) \\&-\, 680400\,{s}^{2}{v}^{10}\cos (2\,v) -725445\,{s}^{8}{v}^{4}\cos (3\,v) \\&-\, 3175200\,\cos (v) {s}^{8}+82350\,{s}^{6}{v}^{9}\sin (3\,v) \\&-\, 32550\,{s}^{2}{v}^{13}\sin (3\,v) -4191\,\sin (v) {s}^{8}{v}^{9}\\&+\, 8353\,\cos (v) {s}^{2}{v}^{16}-394740\,\cos (v) {v}^{14}\\&+\, 1358100\,\sin (v) {v}^{15}-303\,{s}^{8}{v}^{9}\sin (3\,v) \\&+\, 22680\,{s}^{2}{v}^{12}\cos (3\,v) -6\,{s}^{8}{v}^{11}\sin (3\,v) \\&-\, 1164240\,{s}^{2}{v}^{12}-33120\,{s}^{2}{v}^{14}+528\,{s}^{6}{v}^{12}\\&-\, 176\,{s}^{2}{v}^{16}-861840\,{s}^{6}{v}^{6}\cos (2\,v) \\&-\, 427680\,{s}^{6}{v}^{7}\sin (2\,v) -1200\,{s}^{6}{v}^{11}\sin (2\,v) \\&-\, 117600\,{s}^{2}{v}^{13}\sin (2\,v) +1663200\,{s}^{2}{v}^{9}\sin (2\,v) \\&-\, 71190\,{s}^{4}{v}^{11}\sin (3\,v) +8675100\,{v}^{10}\cos (3\,v) \\&-\, 2319975\,\sin (v) {s}^{2}{v}^{9}-3175200\,{s}^{6}{v}^{5}\sin (2\,v) \\&-\, 335475\,{s}^{2}{v}^{9}\sin (3\,v) -2721600\,{s}^{8}{v}^{3}\sin (2\,v) \\&+\, 3075975\,{s}^{6}{v}^{5}\sin (3\,v) +1828575\,{s}^{8}{v}^{3}\sin (3\,v) \\&-\, 12960\,{s}^{2}{v}^{14}\cos (2\,v) +6669810\,\sin (v) {s}^{4}{v}^{11}\\&+\, 7392\,{s}^{6}{v}^{10}\cos (2\,v) +28755\,\cos (v) {s}^{6}{v}^{12}\\&+\, 11520\,{s}^{8}{v}^{7}\sin (2\,v) -1399545\,{s}^{4}{v}^{9}\sin (3\,v) \\&-\, 2373\,{s}^{4}{v}^{13}\sin (3\,v) -138418875\,\sin (v) {s}^{4}{v}^{7}\\&+\, 2653875\,\sin (v) {s}^{2}{v}^{11}+1115505\,{s}^{6}{v}^{7}\sin (3\,v) \\&-\, 1305\,{s}^{2}{v}^{15}\sin (3\,v) +559440\,{s}^{2}{v}^{12}\cos (2\,v) \\&-\, 397440\,{v}^{14}+30240\,{s}^{8}{v}^{6}\cos (2\,v) \\&+\, 40325040\,{s}^{6}{v}^{6}-172594800\,{s}^{6}{v}^{4}\\&-\, 2192400\,{s}^{6}{v}^{8}+30\,{s}^{2}{v}^{17}\sin (3\,v) -332325\,{s}^{2}{v}^{11}\sin (3\,v) \\&+\, 10949400\,\sin (v) {v}^{13}-38102400\,\cos (v) {s}^{6}{v}^{2}\\&-\, 537\,\cos (v) {s}^{4}{v}^{16}+179\,\cos (v) {s}^{2}{v}^{18}\\&-\, 352\,{s}^{8}{v}^{10}+4527495\,{s}^{6}{v}^{6}\cos (3\,v) \\&+\, 793800\,{s}^{2}{v}^{8}\cos (3\,v) -15660\,{v}^{15}\sin (3\,v) \\&+\, 76204800\,{s}^{6}{v}^{2}+121352175\,\cos (v) {s}^{4}{v}^{8}\\&+\, 22059135\,\sin (v) {s}^{4}{v}^{9}+10039545\,\sin (v) {s}^{6}{v}^{7}\\&+\, 13452075\,\sin (v) {s}^{6}{v}^{5}-1630125\,\sin (v) {s}^{8}{v}^{3}\\&-\, 179\,\cos (v) {s}^{8}{v}^{12}+20520\,\sin (v) {v}^{17}\\&+\, 12852000\,{s}^{8}{v}^{2}+2148\,\cos (v) {v}^{18}\\&+\, 272160\,{s}^{4}{v}^{10}\cos (3\,v) -8396640\,{s}^{8}{v}^{4}\\&+\, 816480\,{s}^{8}{v}^{6}+2394\,\sin (v) {s}^{6}{v}^{13}-342\,\sin (v) {s}^{8}{v}^{11}\\&+\, 480\,{s}^{8}{v}^{9}\sin (2\,v) -109620\,{s}^{8}{v}^{6}\cos (3\,v) \\&+\, 15884505\,\cos (v) {s}^{6}{v}^{6}-6474060\,\cos (v) {s}^{6}{v}^{8}\\&+\, 9525600\,{v}^{8}\cos (3\,v) -7813260\,\cos (v) {s}^{4}{v}^{10}\\&+\, 836640\,{s}^{8}{v}^{4}\cos (2\,v) -2112\,{v}^{16}+6350400\,{s}^{8}\\&+\, 2381400\,{s}^{4}{v}^{6}\cos (3\,v) +84240\,{s}^{6}{v}^{8}\cos (2\,v) \\&+\, 247320\,{s}^{6}{v}^{8}\cos (3\,v) -23360400\,{s}^{6}{v}^{4}\cos (2\,v) \\&+\, 912450\,\sin (v) {s}^{2}{v}^{13} \end{aligned}$$
$$\begin{aligned} PLM_{10}\left( s,v \right)= & {} -35607600\,{s}^{6}{v}^{4}\cos (4\,v) +191160\,{v}^{14}\cos (3\,v) +668\,{v}^{12}{s}^{8}\cos (2\,v)\\&-\, 420210\,{v}^{13}\sin (3\,v) +36514800\,{v}^{10}\cos (3\,v) \\&+\, 78\,{s}^{6}{v}^{12}\cos (4\,v) -7098\,{s}^{6}{v}^{10}\cos (4\,v) \\&-\, 621495\,{v}^{13}\sin (4\,v) +7151760\,\cos (v) {s}^{2}{v}^{12}\\&+\, 5244750\,{s}^{6}{v}^{5}\sin (4\,v) -8344350\,{v}^{11}\sin (3\,v) \\&-\, 57153600\,{s}^{2}{v}^{7}\sin (2\,v) -9686250\,{s}^{2}{v}^{10}\cos (4\,v) \\&+\, 6644\,{v}^{11}{s}^{8}\sin (2\,v) +20087760\,\sin (v) {s}^{2}{v}^{13}\\&-\, 42480720\,\cos (v) {s}^{6}{v}^{8}+18325440\,\cos (v) {s}^{8}{v}^{6}\\&+\, 259386\,{v}^{17}\sin (2\,v) +147420\,{s}^{8}{v}^{6}\cos (4\,v) \\&+\, 2148\,\cos (v) {s}^{4}{v}^{16}-1432\,\cos (v) {s}^{6}{v}^{14}\\&-\, 8456\,{v}^{13}{s}^{6}\sin (2\,v) +106709400\,{v}^{12}\cos (2\,v) \\&-\, 6600825\,{v}^{11}\sin (4\,v) -6350400\,{s}^{8}\cos (4\,v) \\&-\, 1432\,\cos (v) {s}^{2}{v}^{18}+3876\,\sin (v) {s}^{8}{v}^{11}\\&+\, 31253040\,\cos (v) {s}^{4}{v}^{10}+6621\,{s}^{8}{v}^{8}\cos (4\,v) \\&-\, 453\,{s}^{8}{v}^{9}\sin (4\,v) -34884\,{v}^{18}\cos (2\,v) \\&+\, 7372890\,{v}^{13}\sin (2\,v) +55310040\,\sin (v) {s}^{6}{v}^{7}\\&+\, 1174770\,{s}^{6}{v}^{7}\sin (4\,v) +14956560\,\sin (v) {s}^{6}{v}^{9}\\&-\, 1053\,{v}^{16}\cos (4\,v) -26679240\,\sin (v) {s}^{4}{v}^{11}\\&+\, 6350400\,{s}^{8}-4859190\,{s}^{6}{v}^{6}\cos (4\,v) \\&-\, 4447260\,\sin (v) {s}^{8}{v}^{7}-1208\,{v}^{17}{s}^{2}\sin (2\,v) \\&+\, 12700800\,{s}^{8}\cos (3\,v) -1083\,{v}^{17}\sin (4\,v) \\&+\, 839790\,{s}^{2}{v}^{11}\sin (4\,v) -172169550\,{v}^{11}\sin (2\,v) +712605600\,\cos (v) {s}^{6}{v}^{4}\\&+\, 9525600\,\cos (v) {s}^{4}{v}^{6}+15876000\,\cos (v) {s}^{2}{v}^{8}\\&+\, 201625200\,\sin (v) {s}^{8}v-100699200\,\sin (v) {s}^{6}{v}^{3}\\&-\, 200037600\,\sin (v) {s}^{4}{v}^{5}-152409600\,\cos (v) {s}^{6}{v}^{2}\\&-\, 50058\,\sin (v) {v}^{17}+2467\,{v}^{20}\\&+\, 66868200\,{s}^{8}{v}^{4}\cos (2\,v) -32130\,{v}^{15}\sin (4\,v) \\&-\, 650160\,{s}^{2}{v}^{12}\cos (3\,v) +2425140\,{v}^{15}\sin (2\,v) \\&+\, 5598180\,{s}^{4}{v}^{9}\sin (3\,v) +5238\,{s}^{8}{v}^{8}\cos (3\,v) \\&-\, 10\,{v}^{19}\sin (4\,v) +25924\,{s}^{8}{v}^{10}\cos (2\,v) \\&+\, 3020\,{v}^{19}\sin (2\,v) -188470800\,{s}^{6}{v}^{6}\cos (2\,v) \\&-\, 224916\,{s}^{2}{v}^{15}\sin (2\,v) +340540200\,\cos (v) {s}^{2}{v}^{10}\\&-\, 63997290\,\cos (v) {v}^{12}+275562000\,\cos (v) {v}^{10}\\&-\, 38102400\,\cos (v) {v}^{8}-130410000\,\sin (v) {v}^{9}\\&+\, 195284250\,\sin (v) {v}^{11}-314280\,{s}^{6}{v}^{8}\cos (4\,v) \\&+\, 70345485\,{s}^{8}{v}^{4}-101448\,{s}^{6}{v}^{12}\cos (2\,v) \\&-\, 3702780\,\sin (v) {v}^{15}+76204800\,{s}^{2}{v}^{8}\cos (2\,v) \\&+\, 4934\,{v}^{14}{s}^{6}-1295595\,{v}^{12}\cos (4\,v) \\&-\, 3475080\,{s}^{2}{v}^{11}\sin (3\,v) -6216\,{s}^{2}{v}^{15}\sin (3\,v) \\&+\, 160806\,\sin (v) {s}^{8}{v}^{9}+10666\,\cos (v) {s}^{8}{v}^{10}\\&-\, 65784\,\cos (v) {s}^{6}{v}^{12}-19896840\,{s}^{6}{v}^{8}\cos (2\,v) \\&-\, 197429400\,\sin (v) {s}^{6}{v}^{5}-28533960\,\sin (v) {s}^{2}{v}^{11}\\&-\, 7638120\,{s}^{2}{v}^{13}\sin (2\,v) -1088640\,{s}^{4}{v}^{10}\cos (3\,v) \\&+\, 24403680\,{s}^{2}{v}^{12}-3431970\,{s}^{2}{v}^{14}\\&+\, 428010\,{s}^{6}{v}^{12}-280098000\,{s}^{6}{v}^{4}\\&+\, 56756700\,{s}^{4}{v}^{7}\sin (3\,v) -51672600\,{s}^{2}{v}^{9}\sin (3\,v) \\&+\, 110408\,{s}^{2}{v}^{16}\cos (2\,v) +2\,{v}^{12}{s}^{8}\cos (3\,v) \\&-\, 52920\,{s}^{8}{v}^{6}\cos (3\,v) -1336\,{v}^{14}{s}^{6}\cos (2\,v) \\&+\, 2343600\,{s}^{8}{v}^{2}\cos (4\,v) +278487720\,\cos (v) {s}^{6}{v}^{6}-485408700\,\cos (v) {s}^{4}{v}^{8}\\&+\, 56\,{s}^{2}{v}^{16}\cos (3\,v) -9525600\,{s}^{4}{v}^{6}\cos (3\,v) \\&+\, 28433160\,{s}^{8}{v}^{6}-11592\,\sin (v) {s}^{2}{v}^{15}\\&-\, 15816\,\cos (v) {s}^{6}{v}^{10}-9752400\,{v}^{9}\sin (3\,v) \\&+\, 2\,\cos (3\,v) {v}^{20}-16443000\,{s}^{6}{v}^{5}\sin (3\,v) \\&+\, 63336\,{s}^{6}{v}^{10}\cos (3\,v) -11113200\,{s}^{2}{v}^{8}\cos (4\,v) \\&+\, 53326350\,{s}^{8}{v}^{3}\sin (2\,v) +122301\,{v}^{18}\\&-\, 1159407\,{v}^{16}-14453640\,{v}^{14}-100018800\,{v}^{10}\\&-\, 12879405\,{v}^{12}-194140800\,{v}^{10}\cos (2\,v) \\&+\, 19051200\,{v}^{8}+78\,{v}^{18}\cos (3\,v) \\&-\, 4602\,{s}^{8}{v}^{9}\sin (3\,v) -1851480\,{s}^{6}{v}^{10}\cos (2\,v) \\&-\, 199920\,{s}^{2}{v}^{13}\sin (3\,v) -61020\,{v}^{14}\cos (4\,v) \\&+\, 23110920\,{s}^{2}{v}^{12}\cos (2\,v) -2\,{v}^{18}{s}^{2}\cos (4\,v) \\&+\, 3214890\,{v}^{12}\cos (3\,v) -513000\,{s}^{6}{v}^{7}\sin (3\,v) \\&+\, 2398680\,{s}^{2}{v}^{14}\cos (2\,v) -79380000\,{s}^{8}v\sin (2\,v) \\&-\, 412980\,{s}^{8}{v}^{8}\cos (2\,v) +30660\,{s}^{2}{v}^{13}\sin (4\,v) \\&-\, 270318\,\cos (v) {s}^{8}{v}^{8}-1212\,{s}^{4}{v}^{14}\cos (3\,v) \\&+\, 5940\,{v}^{15}\sin (3\,v) -10615320\,{s}^{6}{v}^{9}\sin (2\,v) \\&+\, 284760\,{s}^{4}{v}^{11}\sin (3\,v) +24844050\,{s}^{2}{v}^{9}\sin (4\,v) \\&+\, 384966\,{s}^{8}{v}^{9}\sin (2\,v) -{v}^{12}{s}^{8}\cos (4\,v) \\&-\, 57153600\,{s}^{2}{v}^{7}\sin (3\,v) +10904220\,{v}^{14}\cos (2\,v) \\&-\, 33339600\,{s}^{8}v\sin (3\,v) -464297400\,\sin (v) {s}^{2}{v}^{9}\\&-\, 35002800\,\cos (v) {s}^{8}{v}^{2}+10001880\,{s}^{6}{v}^{6}\cos (3\,v) \\&+\, 32794740\,{s}^{6}{v}^{7}\sin (2\,v) -19051200\,{v}^{8}\cos (4\,v) \\&-\, 56700\,{s}^{4}{v}^{12}\cos (3\,v) -20326950\,{s}^{2}{v}^{10}\\&-\, 2069550\,{s}^{8}{v}^{3}\sin (3\,v) +3728025\,{s}^{8}{v}^{3}\sin (4\,v) \\&+\, 1944\,{s}^{6}{v}^{12}\cos (3\,v) +66679200\,{s}^{4}{v}^{5}\sin (3\,v) \\&-\, 4934\,{v}^{18}{s}^{2}+71215200\,{s}^{6}{v}^{4}\cos (3\,v) \\&-\, 866\,{s}^{8}{v}^{10}\cos (3\,v) +248535\,{s}^{8}{v}^{5}\sin (4\,v) \\&+\, 152409600\,{s}^{6}{v}^{2}\cos (3\,v) +358\,\cos (v) {s}^{8}{v}^{12}\\&+\, 10073700\,{s}^{8}{v}^{6}\cos (2\,v) +63504000\,{s}^{8}{v}^{2}\cos (2\,v) \\&+\, 8172258\,{s}^{6}{v}^{10}-13396320\,{s}^{6}{v}^{8}\\&-\, 8\,{v}^{18}{s}^{2}\cos (3\,v) -468115200\,{s}^{6}{v}^{4}\cos (2\,v) \\&+\, 38102400\,{v}^{8}\cos (3\,v) -153090\,{s}^{8}{v}^{5}\sin (3\,v) \\&+\, 79740\,{s}^{6}{v}^{9}\sin (4\,v) +12\,{s}^{4}{v}^{16}\cos (3\,v) \\&-\, 9922500\,{s}^{4}{v}^{8}\cos (3\,v) +1285515\,{s}^{8}{v}^{4}\cos (4\,v) \\&-\, 8\,{v}^{14}{s}^{6}\cos (3\,v) +525420\,\cos (v) {s}^{4}{v}^{12}\\&+\, 323640\,\cos (v) {s}^{2}{v}^{14}+100699200\,{s}^{6}{v}^{3}\sin (2\,v) \\&+\, 28\,{s}^{6}{v}^{13}\sin (4\,v) -347178\,{s}^{2}{v}^{16}\\&-\, 12700800\,\cos (v) {s}^{8}-630636\,{s}^{6}{v}^{11}\sin (2\,v) \\&-\, 22\,{s}^{8}{v}^{11}\sin (4\,v) +5509350\,{s}^{8}{v}^{5}\sin (2\,v) \\&+\, 259969500\,{s}^{2}{v}^{9}\sin (2\,v) -24494400\,{s}^{6}{v}^{3}\sin (3\,v) \\&+\, 678\,{s}^{2}{v}^{15}\sin (4\,v) -5400\,{s}^{2}{v}^{14}\cos (3\,v) \\&-\, 15800400\,{s}^{8}{v}^{2}\cos (3\,v) -15044400\,{s}^{8}{v}^{2}\\&+\, 7482\,\cos (v) {v}^{18}-2467\,{v}^{12}{s}^{8}\\&+\, 63\,{v}^{18}\cos (4\,v) +80230500\,{s}^{6}{v}^{5}\sin (2\,v) \\&-\, 334660410\,{s}^{6}{v}^{6}+726\,{v}^{17}\sin (3\,v) \\&+\, 14288400\,{s}^{8}v\sin (4\,v) +28576800\,{s}^{2}{v}^{7}\sin (4\,v) \\&-\, 270\,{s}^{2}{v}^{16}\cos (4\,v) +2\,{v}^{14}{s}^{6}\cos (4\,v) \\&-\, 15750\,{s}^{2}{v}^{14}\cos (4\,v) +5046\,{v}^{16}\cos (3\,v) \\&+\, 129\,{s}^{8}{v}^{10}\cos (4\,v) -297183600\,{s}^{2}{v}^{10}\cos (2\,v) \\&-\, 567000\,{s}^{2}{v}^{12}\cos (4\,v) -65091600\,{s}^{2}{v}^{8}\\&-\, 17917200\,{v}^{10}\cos (4\,v) +93895200\,{v}^{9}\sin (2\,v) \\&-\, 59416\,\cos (v) {s}^{2}{v}^{16}-529320\,\sin (v) {s}^{6}{v}^{11}\\&+\, 430164\,\sin (v) {s}^{4}{v}^{13}-1966230\,{s}^{8}{v}^{4}\cos (3\,v) \\&+\, 107052\,\cos (v) {s}^{4}{v}^{14}-76204800\,{s}^{6}{v}^{2}\cos (4\,v) \\&+\, 264\,{s}^{4}{v}^{15}\sin (3\,v) -135705780\,{s}^{2}{v}^{11}\sin (2\,v) \\&+\, 600\,{s}^{6}{v}^{11}\sin (3\,v) -88236540\,\sin (v) {s}^{4}{v}^{9}\\&+\, 2778\,{s}^{6}{v}^{11}\sin (4\,v) +171460800\,\sin (v) {s}^{2}{v}^{7}\\&+\, 76204800\,{s}^{6}{v}^{2}-203133\,{s}^{8}{v}^{10}\\&+\, 563760\,{s}^{6}{v}^{8}\cos (3\,v) -20460\,{s}^{8}{v}^{7}\sin (3\,v) \\&-\, 130182570\,\cos (v) {s}^{8}{v}^{4}+358\,\cos (v) {v}^{20}\\&-\, 224\,{s}^{6}{v}^{13}\sin (3\,v) +144720\,{s}^{6}{v}^{9}\sin (3\,v) \\&-\, 668\,{v}^{20}\cos (2\,v) -128\,{s}^{2}{v}^{17}\sin (3\,v) \\&+\, 48271230\,\sin (v) {v}^{13}-3535920\,\cos (v) {v}^{14}\\&-\, 6804000\,{s}^{6}{v}^{3}\sin (4\,v) +{v}^{20}\cos (4\,v) \\&-\, 15876000\,{s}^{2}{v}^{8}\cos (3\,v) -13343400\,{s}^{2}{v}^{10}\cos (3\,v) \\&+\, 1336\,{v}^{18}{s}^{2}\cos (2\,v) -344046\,\cos (v) {v}^{16}\\&+\, 20\,\sin (3\,v) {v}^{19}+4\,{s}^{2}{v}^{17}\sin (4\,v) \\&+\, 553675500\,\sin (v) {s}^{4}{v}^{7}+68\,{s}^{8}{v}^{11}\sin (3\,v) \\&-\, 7030800\,{v}^{9}\sin (4\,v) +1140\,{v}^{19}\sin (v) \\&-\, 2987601\,{s}^{8}{v}^{8}+9492\,{s}^{4}{v}^{13}\sin (3\,v) \\&-\, 12768\,\sin (v) {s}^{6}{v}^{13}+15048\,\sin (v) {s}^{4}{v}^{15}\\&-\, 7296\,\sin (v) {s}^{2}{v}^{17}-109005750\,\sin (v) {s}^{8}{v}^{3}\\&+\, 2058060\,{s}^{8}{v}^{7}\sin (2\,v) +441780\,{v}^{16}\cos (2\,v) \\&+\, 14226030\,\sin (v){s}^{8}{v}^{5}+2370\,{s}^{8}{v}^{7}\sin (4\,v) \end{aligned}$$

where \(PLM_{j}\left( s,v \right) , \, \, j=8,9,10\) are the Polynomials of the general Stability Functions of the New Introduced Scheme.

Stability District of the New Introduced Scheme \(\, \equiv \,\) \(s-v\). Figure 5\(\longrightarrow\) \(s-v\) range of Stability District of the New Introduced Scheme.

Fig. 5
figure 5

Determination of the stability district of the new introduced scheme

Fig. 6
figure 6

\(s-v\) district

Conclusion 4

Figure 6 for \(s-v\) \(\longrightarrow\):

  • Colored district of \(s-v\) \(\longrightarrow\) Stabilized district.

  • White district of \(s-v\) \(\longrightarrow\) Unstabilized district.

Conclusion 5

Report on the new nominated Method \(\longrightarrow\):

  • \(s \ne v\) \(\longrightarrow\) stabilized for \(s, \, v\) \(\in\) \(s-v\) \(\backslash\) \(\{\) around first diagonal \(\}\).

  • \(s = v\) \(\longrightarrow\) stabilized for \(s, \, v\) \(\in\) \(\{\) around first diagonal \(\}\).

Conclusion 6

Figure 6. \(\longrightarrow\) the new deployed procedure is P-stable\(\, \equiv \, \langle s-v \rangle \equiv \left( 0, \infty \right)\).

The Table 1\(\longrightarrow\) intervals of periodicity of Methods of (4).

Table 1 Intervals of periodicity of the family (4)

(4) \(+\) (11) \(+\) Theorem 2\(+\) Stage 5 of Fig. 1\(+\) Table 1\(\Longrightarrow\)

Theorem 3

The new deployed Method:

  • has 4 levels,

  • Algebraic Order \(\longrightarrow\) 14,

  • \(PhL = 0\),

  • \(DPL_{1}=DPL_{2}=DPL_{3}=DPL_{4}=DPL_{3}=DPL_{5}=DPL_{6}=0\),

  • is P-stable.

where \(PhL = {\text{phase}}{-}{\text{lag}}\) and \(DPL_{j} = {\text{derivative of the phase--lag of order j}}\)

4 Numerical tests

Figure 7\(\longrightarrow\) Valuing the newly deployed Algorithm.

Fig. 7
figure 7

Valuing the new proposed algorithm

4.1 Local error control procedure

Local Error Control Procedure \(\longrightarrow\) Local Truncation Error’s Control Procedure.

Local Error Control Procedure \({\mathop {\longrightarrow }\limits ^{includes}}\): variable–step process (see in [75, 143] and references therein).

Table 2\(\longrightarrow\) Papers on the Subject (see [1]–[143]).

Table 2 Literature. Notes: (1) Multistage: Runge–Kutta and of Runge–Kutta Nyström type, P-Stability etc. Involves also multistage schemes with minimal phase–lag. (2) Multistage Exponential: exponentially fitted and trigonometrically fitted Runge–Kutta and Runge–Kutta Nyström Methods. (3) Multistep phase–fitting: Multistep Methods with obliterating phase-lag, obliterating derivatives of the phase–lag, multistep Methods with minimal phase–lag

Note 1 Local Error Control Procedure \(\longrightarrow\) Procedure for the Control of the Local Truncation Error \({\mathop {\longrightarrow }\limits ^{is \, defined\, as}}\):

Definition 1

$$\begin{aligned} Local Error Control Procedure=\mid \{\beta \lambda \}^{H}_{n+1} - \{\beta \lambda \}^{L}_{n+1} \mid \end{aligned}$$
(32)

where \(\{\beta \lambda \}^{L}_{n+1}\) \(\longrightarrow\) [86], L \(\longrightarrow\) low algebraic order , \(\{\beta \lambda \}^{H}_{n+1}\) \(\longrightarrow\) Sect. 2, H \(\longrightarrow\) high algebraic order .

In [75], the flowchart for Local Error Control Procedure is displayed.

4.2 Description of the problem

$$\begin{aligned} \{\varvec{\beta \lambda }\}'' = - \varvec{\Psi } \, \{\varvec{\beta \lambda }\} \end{aligned}$$
(33)

and

$$\begin{aligned} \Psi _{ij} = \frac{l_{i} (l_{i}+1)}{x^{2}}\, \psi _{ij} + Potent_{ij} \end{aligned}$$
(34)

and \(Potent_{ij} \rightarrow 0\) as \(x \rightarrow \infty\).

Boundary conditions\({\mathop {\longrightarrow }\limits ^{open \, channels}}\)

$$\begin{aligned} \{\beta \lambda \}_{ij} = 0 \hbox { } at \hbox { } x = 0 \end{aligned}$$
(35)
$$\begin{aligned} \{\beta \lambda \}_{ij} \sim k_{i} x j_{l_{i}}(k_{i} x) \psi _{ij} + \left( \frac{k_{i}}{k_{j}} \right) ^{1/2} K_{ij} k_{i} x n_{l{i}}(k_{i} x) \end{aligned}$$
(36)

where

  • \(j_{l}(x)\) \(\longrightarrow\) spherical Bessel functions and

  • \(n_{l}(x)\) \(\longrightarrow\) spherical Neumann functions.

[62] \(\longrightarrow\):

$$\begin{aligned}&\frac{2 \nu }{\hbar ^{2}}=1000.0, \hbox { } \frac{\nu }{I}=2.351, \hbox { } E=1.1, \\&V_{0}(x)=\frac{1}{x^{12}}-2 \frac{1}{x^{6}}, \hbox { } V_{2}(x)=0.2283 V_{0}(x). \end{aligned}$$

Figure 8\(\longrightarrow\) Flowchart for the problem’s (33) - (35) solution.

Fig. 8
figure 8

Numerical solution for (33)–(35)

Table 3 Computing time (in s) (CT \(=\) real time of computation) and maximum absolute error (MBAST). Parameter acurac is needed for we define acurac=10\(^{-6}\). \(h_length_maximum\) \(\longrightarrow\) maximum stepsize. M \(\longrightarrow\) equation’s number

We use the following schemes:

  • Method 1: Allison’s Algorithm [62],

  • Method 2: See [61],

  • Method 3: See [54],

  • Method 4: See [65],

  • Method 5: See [67],

  • Method 6: See [73],

  • Method 7: See [49],

  • Method 8: See [71],

  • Method 9: See [74],

  • Method 10: See [37],

  • Method 11: See [85],

  • Method 12: See [40],

  • Method 13: See [41],

  • Method 14: See [42],

  • Method 15: See [43],

  • Method 16: See [44],

  • Method 17: Sect. 2.

Table 3\(\longrightarrow\) CT (in seconds) and MBAST for the 16 Methods.

All computations were carried out on a x86-64 compatible PC using double-precision arithmetic data type (64 bits) according to IEEE© Standard 754 for double precision.

5 General conclusion

A new FD method with phase–lag and its derivatives up to order 6 equal to zero is protduced. The theoretical evaluation which is presented in Sect. 3, proves the theoretical superiority of the new introduced scheme. The computational evaluation of the new method, which is based on (33), proves the efficiency of the new scheme.