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| author | Ethan Werner <mail@ethanwerner.com> | 2026-07-01 09:42:39 +0400 |
|---|---|---|
| committer | Ethan Werner <mail@ethanwerner.com> | 2026-07-01 09:42:39 +0400 |
| commit | 07e18043145f3d91c8ea7ec3ad41b3c905585277 (patch) | |
| tree | 2bdeae46973f4bdfce263679a4008ac768011f28 /lib/average_triangle.c | |
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
Diffstat (limited to 'lib/average_triangle.c')
| -rw-r--r-- | lib/average_triangle.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/lib/average_triangle.c b/lib/average_triangle.c new file mode 100644 index 0000000..9ac952d --- /dev/null +++ b/lib/average_triangle.c @@ -0,0 +1,107 @@ +// Triangular Moving Average +// +// average_triangle - tma +// +// A moving average of moving averages +// +// y[i] = +// +// Inputs: 1 +// Outputs: 1 +// Constants: 1 +// +// 012345678901234567890123456789 +// ---------01234567890123456 +// ------------------0 + + +#include <stdlib.h> +#include "ts.h" + + +typedef struct { + uint_t k; +} ts_average_triangle_params_t; + +ts_parameter_t const ts_average_triangle_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 1, .params_size = sizeof(ts_average_triangle_params_t) }; + + +uint_t ts_average_triangle_offset( ts_constant_t const *c ) +{ + ( void )c; + return ( c ? 2 * ( ((ts_average_triangle_params_t *)c)->k - 1 ) : 0 ); +} + +int ts_average_triangle( + 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_average_triangle_p ); + if ( !c ) return -1; + uint_t k = ((ts_average_triangle_params_t *)c)->k; + if (k == 0 || n < k) return -1; + + fp_t rk2 = _ts_reciprocal( _ts_square( k ) ); + uint_t xi = 0; + uint_t yi = 2 * ( k - 1 ); + + fp_t *xsum = malloc(k * sizeof(fp_t)); + if (!xsum) return -1; + uint_t xsumi = 0; + + fp_t sum_of_xsum = 0; + + xsum[0] = 0; + + for (uint_t j = 0; j < n && j < 2 * (k - 1); ++j) y[0][j] = 0; + + fp_t last_sum = 0; + + for( ; xi < k; xi++ ) + { + xsum[xsumi] += x[0][xi]; + last_sum = xsum[xsumi]; + } + + sum_of_xsum = xsum[xsumi]; + xsumi++; + + for( ; xi < 2 * k - 1; xi++ ) + { + xsum[xsumi] = xsum[xsumi - 1] + x[0][xi] - x[0][xi - k]; + last_sum = xsum[xsumi]; + sum_of_xsum += xsum[xsumi]; + xsumi++; + } + + y[0][yi++] = sum_of_xsum * rk2; + + for( ; xi < n; ++xi, ++yi ) + { + if( xsumi == k ) + { + xsumi = 0; + sum_of_xsum -= xsum[xsumi]; + xsum[xsumi] = last_sum + x[0][xi] - x[0][xi - k]; + } + else + { + sum_of_xsum -= xsum[xsumi]; + xsum[xsumi] = last_sum + x[0][xi] - x[0][xi - k]; + } + + last_sum = xsum[xsumi]; + sum_of_xsum += xsum[xsumi]; + y[0][yi] = sum_of_xsum * rk2; + + xsumi++; + } + + free(xsum); + return 0; +} + + + |