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-rw-r--r--lib/log1pm1.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/lib/log1pm1.c b/lib/log1pm1.c
new file mode 100644
index 0000000..ea9281a
--- /dev/null
+++ b/lib/log1pm1.c
@@ -0,0 +1,41 @@
+// Log1pm1
+//
+// log1pm1
+//
+// Log(1+x) - 1
+//
+// ln(1+x) - 1
+//
+// Inputs: 1
+// Outputs: 1
+// Constants: 0
+
+
+#include <math.h>
+#include "ts.h"
+
+ts_parameter_t const ts_log1pm1_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 0, .params_size = 0 };
+
+uint_t ts_log1pm1_offset( ts_constant_t const *c )
+{
+ ( void )c;
+ return ( 0 );
+}
+
+int ts_log1pm1(
+ 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_log1pm1_p );
+ (void)c;
+ for( uint_t i = 0; i < n; ++i )
+ {
+ fp_t xv = x[0][i];
+ if( xv < -1.0 ) { y[0][i] = 0; continue; }
+ y[0][i] = log1p( xv ) - 1.0;
+ }
+ return 0;
+}
+