127 lines
2.5 KiB
MQL5
127 lines
2.5 KiB
MQL5
//+------------------------------------------------------------------+
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//| polevl.mqh |
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//| Copyright 2025, MetaQuotes Ltd. |
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//| https://www.mql5.com |
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//+------------------------------------------------------------------+
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#property copyright "Copyright 2025, MetaQuotes Ltd."
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#property link "https://www.mql5.com"
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#include"config.mqh"
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namespace special
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{
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namespace cephes
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{
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inline double polevl(double x, double &coef[], int N)
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{
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double ans;
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int i;
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int p;
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p = 0;
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ans = coef[p++];
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i = N;
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do
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{
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ans = ans * x + coef[p++];
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}
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while(--i != 0);
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return (ans);
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}
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/* p1evl() */
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/* N
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* Evaluate polynomial when coefficient of x is 1.0.
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* That is, C_{N} is assumed to be 1, and that coefficient
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* is not included in the input array coef.
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* coef must have length N and contain the polynomial coefficients
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* stored as
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* coef[0] = C_{N-1}
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* coef[1] = C_{N-2}
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* ...
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* coef[N-2] = C_1
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* coef[N-1] = C_0
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* Otherwise same as polevl.
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*/
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inline double p1evl(double x, double &coef[], int N)
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{
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double ans;
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int p;
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int i;
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p = 0;
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ans = x + coef[p++];
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i = N - 1;
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do
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ans = ans * x + coef[p++];
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while(--i != 0);
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return (ans);
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}
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/* Evaluate a rational function. See [1]. */
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/* The function ratevl is only used once in cephes/lanczos.h. */
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inline double ratevl(double x, double &num[], int M, double &denom[], int N)
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{
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int i, dir;
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double y, num_ans, denom_ans;
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double absx = abs(x);
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int p;
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if(absx > 1)
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{
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/* Evaluate as a polynomial in 1/x. */
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dir = -1;
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p = M;
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y = 1 / x;
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}
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else
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{
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dir = 1;
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p = 0;
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y = x;
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}
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/* Evaluate the numerator */
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num_ans = num[p];
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p += dir;
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for(i = 1; i <= M; i++)
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{
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num_ans = num_ans * y + num[p];
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p += dir;
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}
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/* Evaluate the denominator */
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if(absx > 1)
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{
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p = N;
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}
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else
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{
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p = 0;
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}
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denom_ans = denom[p];
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p += dir;
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for(i = 1; i <= N; i++)
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{
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denom_ans = denom_ans * y + denom[p];
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p += dir;
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}
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if(absx > 1)
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{
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i = M - N;
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return pow(x, i) * num_ans / denom_ans;
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}
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else
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{
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return num_ans / denom_ans;
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}
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}
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} // namespace cephes
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} // namespace special
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