From 07e18043145f3d91c8ea7ec3ad41b3c905585277 Mon Sep 17 00:00:00 2001 From: Ethan Werner Date: Wed, 1 Jul 2026 09:42:39 +0400 Subject: initial commit: ts time series analysis library v0.1.0 - 354 financial and mathematical time-series indicators - Uniform C11 API with consistent function signatures - 349 passing tests with -Werror - Static and shared library builds - pkg-config integration - Python bindings - Fuzzing and sanitizer support - Security hardening flags --- lib/chebyshev_t.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 lib/chebyshev_t.c (limited to 'lib/chebyshev_t.c') diff --git a/lib/chebyshev_t.c b/lib/chebyshev_t.c new file mode 100644 index 0000000..a0230b8 --- /dev/null +++ b/lib/chebyshev_t.c @@ -0,0 +1,61 @@ +// Chebyshev Polynomial of the First Kind +// +// chebyshev_t - T_n(x) +// +// T_0 = 1, T_1 = x, T_n = 2x*T_(n-1) - T_(n-2) +// +// Inputs: 2 (x, n) +// Outputs: 1 (T_n(x)) +// Constants: 0 + +#include +#include "ts.h" + + +ts_parameter_t const ts_chebyshev_t_p = { .n_inputs = 2, .n_outputs = 1, .n_constants = 0, .params_size = 0 }; + +uint_t ts_chebyshev_t_offset( ts_constant_t const *c ) +{ + ( void )c; + return ( 0 ); +} + +int ts_chebyshev_t( + fp_t * const *y, uint_t y_n, + fp_t const * const *x, uint_t x_n, + uint_t n, ts_constant_t const *c +) +{ + TS_PROLOGUE( ts_chebyshev_t_p ); + (void)c; + for( uint_t i = 0; i < n; ++i ) + { + fp_t xv = x[0][i]; + uint_t n_val = (uint_t)x[1][i]; + if (x[1][i] < 0 || x[1][i] > 10000) { y[0][i] = 0; continue; } + if( n_val == 0 ) + { + y[0][i] = 1.0; + } + else if( n_val == 1 ) + { + y[0][i] = xv; + } + else + { + fp_t t0 = 1.0; + fp_t t1 = xv; + for( uint_t k = 2; k <= n_val; ++k ) + { + fp_t t2 = 2.0 * xv * t1 - t0; + t0 = t1; + t1 = t2; + } + y[0][i] = t1; + } + } + return 0; +} + + + -- cgit v1.3.1