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authorEthan Werner <mail@ethanwerner.com>2026-07-01 09:42:39 +0400
committerEthan Werner <mail@ethanwerner.com>2026-07-01 09:42:39 +0400
commit07e18043145f3d91c8ea7ec3ad41b3c905585277 (patch)
tree2bdeae46973f4bdfce263679a4008ac768011f28 /lib/average_exponential_double.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_exponential_double.c')
-rw-r--r--lib/average_exponential_double.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/lib/average_exponential_double.c b/lib/average_exponential_double.c
new file mode 100644
index 0000000..eeb890f
--- /dev/null
+++ b/lib/average_exponential_double.c
@@ -0,0 +1,57 @@
+// Double Exponential Moving Average
+//
+// average_exponential_double - dema
+//
+// y[i] =
+//
+// Inputs: 1
+// Outputs: 1
+// Constants: 1
+
+
+#include <math.h>
+#include "ts.h"
+
+
+typedef struct {
+ fp_t a;
+} ts_average_exponential_double_params_t;
+
+ts_parameter_t const ts_average_exponential_double_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 1, .params_size = sizeof(ts_average_exponential_double_params_t) };
+
+
+uint_t ts_average_exponential_double_offset( ts_constant_t const *c )
+{
+ ( void )c;
+ return ( 0 );
+}
+
+int ts_average_exponential_double(
+ 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_exponential_double_p );
+ if ( !c ) return -1;
+ TS_CHECK_INPUT(x, x_n, n);
+ fp_t a = ((ts_average_exponential_double_params_t *)c)->a;
+ if (a == 0 || n == 0) return -1;
+
+ fp_t ema1 = x[0][0];
+ fp_t ema2 = x[0][0];
+
+ y[0][0] = x[0][0];
+
+ for( uint_t i = 1; i < n; ++i )
+ {
+ ema1 = ema1 + a * ( x[0][i] - ema1 );
+ ema2 = ema2 + a * ( ema1 - ema2 );
+
+ y[0][i] = 2 * ema1 - ema2;
+ }
+ return 0;
+}
+
+
+