diff options
Diffstat (limited to 'lib/hermite.c')
| -rw-r--r-- | lib/hermite.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/hermite.c b/lib/hermite.c new file mode 100644 index 0000000..0418c6b --- /dev/null +++ b/lib/hermite.c @@ -0,0 +1,64 @@ +// Hermite +// +// hermite +// +// Hermite polynomial +// +// H_n(x) via recurrence relation +// +// Inputs: 2 +// Outputs: 1 +// Constants: 0 + + +#include <math.h> +#include "ts.h" + + +ts_parameter_t const ts_hermite_p = { .n_inputs = 2, .n_outputs = 1, .n_constants = 0, .params_size = 0 }; + +uint_t ts_hermite_offset( ts_constant_t const *c ) +{ + ( void )c; + return ( 0 ); +} + +int ts_hermite( + 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_hermite_p ); + (void)c; + for( uint_t i = 0; i < n; ++i ) + { + fp_t xv = x[0][i]; + if (x[1][i] < 0 || x[1][i] > 10000) { y[0][i] = 0; continue; } + uint_t n_val = (uint_t)x[1][i]; + if( n_val == 0 ) + { + y[0][i] = 1.0; + } + else if( n_val == 1 ) + { + y[0][i] = 2.0 * xv; + } + else + { + fp_t h0 = 1.0; + fp_t h1 = 2.0 * xv; + for( uint_t k = 2; k <= n_val; ++k ) + { + fp_t h2 = 2.0 * xv * h1 - 2.0 * (fp_t)(k - 1) * h0; + h0 = h1; + h1 = h2; + } + y[0][i] = h1; + } + } + return 0; +} + + + |