Merge branch 'main' of github.com:seamplex/feenox

Author: gtheler

ChangeLog.md

@@ -1,3 +1,7 @@
+# Development (current)
+
+ * functions `vecmean`, `vecvariance` and `vecsd`
+
 # v1.2 (Sep 2025)
 
  * VTK/VTU writer now supports sparse or unsorted node tags

src/feenox.h

@@ -131,7 +131,7 @@ extern "C++" {
 // number of internal functions, functional and vector functions
 #define N_BUILTIN_FUNCTIONS         70
 #define N_BUILTIN_FUNCTIONALS       8
-#define N_BUILTIN_VECTOR_FUNCTIONS  8
+#define N_BUILTIN_VECTOR_FUNCTIONS  11
 
 // no son enums porque hacemos operaciones con las mascaras de abajo
 #define EXPR_UNDEFINED                            0 
@@ -470,15 +470,14 @@ struct vector_t {
   int used;
   int assigned_init;
   int assigned_zero;
-  
+
   expr_t size_expr;
   int size;
 
   gsl_vector *value;
   gsl_vector *initial_transient;
   gsl_vector *initial_static;
 
-  
   // linked list with the expressions of the initial elements
   expr_t *datas;
 

src/math/builtin_vectorfunctions.c

@@ -30,6 +30,9 @@ double feenox_builtin_vecminindex(vector_t **);
 double feenox_builtin_vecmaxindex(vector_t **);
 double feenox_builtin_vecsum(vector_t **);
 double feenox_builtin_vecsize(vector_t **);
+double feenox_builtin_vecmean(vector_t **);
+double feenox_builtin_vecvariance(vector_t **);
+double feenox_builtin_vecsd(vector_t **);
 
 
 struct builtin_vectorfunction_t builtin_vectorfunction[N_BUILTIN_VECTOR_FUNCTIONS] = {
@@ -41,6 +44,9 @@ struct builtin_vectorfunction_t builtin_vectorfunction[N_BUILTIN_VECTOR_FUNCTION
     {"vecminindex",         1, 1, &feenox_builtin_vecminindex},
     {"vecmaxindex",         1, 1, &feenox_builtin_vecmaxindex},
     {"vecsum",              1, 1, &feenox_builtin_vecsum},
+    {"vecmean",             1, 1, &feenox_builtin_vecmean},
+    {"vecvariance",         1, 1, &feenox_builtin_vecvariance},
+    {"vecsd",               1, 1, &feenox_builtin_vecsd},
 };
 
 ///fv+vecsize+usage vecsize(b)
@@ -188,3 +194,39 @@ double feenox_builtin_vecdot(vector_t **arg) {
   return s;
 }
 
+///fv+vecmean+usage vecmean(a)
+///fv+vecmean+math \hat{\vec{a}} = \frac{1}{\text{vecsize}(\vec{a})} \cdot \sum_{i=1}^{\text{vecsize}(\vec{a})} a_i
+///fv+vecmean+desc Computes the mean value of the elements of vector $\vec{a}$.
+double feenox_builtin_vecmean(vector_t **arg) {
+
+  if (!arg[0]->initialized) {
+    feenox_vector_init(arg[0], FEENOX_VECTOR_INITIAL);
+  }
+
+  return gsl_stats_mean(arg[0]->value->data, arg[0]->value->stride, arg[0]->size);
+}
+
+///fv+vecvariance+usage vecvariance(a)
+///fv+vecvariance+math \hat{\Sigma_\vec{a}} = \frac{1}{\text{vecsize}(\vec{a}) -1} \cdot \sum_{i=1}^{\text{vecsize}(\vec{a})} (a_i - \hat{\vec{a}})^2
+///fv+vecvariance+desc Computes the variance of the elements of vector $\vec{a}$.
+double feenox_builtin_vecvariance(vector_t **arg) {
+
+  if (!arg[0]->initialized) {
+    feenox_vector_init(arg[0], FEENOX_VECTOR_INITIAL);
+  }
+
+  return gsl_stats_variance(arg[0]->value->data, arg[0]->value->stride, arg[0]->size);
+}
+
+///fv+vecsd+usage vecsd(a)
+///fv+vecsd+math \sqrt(\hat{\Sigma_\vec{a}}) = \sqrt{\frac{1}{\text{vecsize}(\vec{a}) -1} \cdot \sum_{i=1}^{\text{vecsize}(\vec{a})} (a_i - \hat{\vec{a}})^2}
+///fv+vecsd+desc Computes the standar deviation of the elements of vector $\vec{a}$.
+///fv+vecsd+desc This is the square root of the variance `vecvariance(a)`.
+double feenox_builtin_vecsd(vector_t **arg) {
+
+  if (!arg[0]->initialized) {
+    feenox_vector_init(arg[0], FEENOX_VECTOR_INITIAL);
+  }
+
+  return gsl_stats_sd(arg[0]->value->data, arg[0]->value->stride, arg[0]->size);
+}

tests/stats.fee

@@ -0,0 +1,2 @@
+VECTOR r[10] DATA +1 +2 +2 -1 +1 0 +1 +1.5 -1 -1
+PRINTF "%.4f %.4f %.4f" vecmean(r) vecvariance(r) vecsd(r)

tests/vector.sh

@@ -17,3 +17,6 @@ exitifwrong $?
 
 answerdiff fibo_vector.fee
 exitifwrong $?
+
+answer stats.fee "0.5500 1.4694 1.2122"
+exitifwrong $?