add m_determinant

src/experimental/_impl/_m_determinant_impl.scad

@@ -0,0 +1,20 @@
+use <util/slice.scad>;
+
+function _m_determinant_sum(lt, leng, i = 0) =
+    i == leng ? 0 : (lt[i] + _m_determinant_sum(lt, leng, i + 1));
+
+function _m_determinant_sub(matrix, leng, fc) = 
+    let(
+        init_sub_m = [for(i = [1:leng - 1]) matrix[i]],
+        sub_m = [for(i = [0:len(init_sub_m) - 1]) 
+            concat(slice(init_sub_m[i], 0, fc), slice(init_sub_m[i], fc + 1))
+        ],
+        sgn = pow(-1, fc % 2)
+    )
+    sgn * matrix[0][fc] * _m_determinant(sub_m);
+
+function _m_determinant(matrix) = 
+    let(leng = len(matrix))
+    leng == 2 ? matrix[0][0] * matrix[1][1] - matrix[1][0] * matrix[0][1] :
+        let(indices = [for(i = [0:leng - 1]) i])
+        _m_determinant_sum([for(fc = indices) _m_determinant_sub(matrix, leng, fc)], leng);

src/experimental/m_determinant.scad

@@ -0,0 +1,3 @@
+use <experimental/_impl/_m_determinant_impl.scad>;
+
+function m_determinant(matrix) = _m_determinant(matrix);