Add is_finite method to vectors and matrices.

This method is useful in debug to error early when some kind of
singularity is encountered.

src/matrix.rs

@@ -106,6 +106,11 @@ impl<S: BaseFloat> Matrix2<S> {
 
         Matrix2::new(c, s, -s, c)
     }
+
+    /// Are all entries in the matrix finite.
+    pub fn is_finite(&self) -> bool {
+        self.x.is_finite() && self.y.is_finite()
+    }
 }
 
 impl<S: BaseFloat> Matrix3<S> {
@@ -205,6 +210,11 @@ impl<S: BaseFloat> Matrix3<S> {
             _1subc * axis.z * axis.z + c,
         )
     }
+
+    /// Are all entries in the matrix finite.
+    pub fn is_finite(&self) -> bool {
+        self.x.is_finite() && self.y.is_finite() && self.z.is_finite()
+    }
 }
 
 impl<S: BaseFloat> Matrix4<S> {
@@ -357,6 +367,11 @@ impl<S: BaseFloat> Matrix4<S> {
             S::zero(), S::zero(), S::zero(), S::one(),
         )
     }
+
+    /// Are all entries in the matrix finite.
+    pub fn is_finite(&self) -> bool {
+        self.w.is_finite() && self.x.is_finite() && self.y.is_finite() && self.z.is_finite()
+    }
 }
 
 impl<S: BaseFloat> Zero for Matrix2<S> {

src/vector.rs

@@ -118,6 +118,13 @@ macro_rules! impl_vector {
             $VectorN::new($($field),+)
         }
 
+        impl<S: BaseFloat> $VectorN<S> {
+            /// True if all entries in the vector are finite
+            pub fn is_finite(&self) -> bool {
+                $(self.$field.is_finite())&&+
+            }
+        }
+
         impl<S: NumCast + Copy> $VectorN<S> {
             /// Component-wise casting to another type.
             #[inline]
@@ -1323,6 +1330,14 @@ mod tests {
                 assert_eq!(v, &VECTOR2);
             }
         }
+
+        #[test]
+        fn test_is_finite() {
+            use num_traits::Float;
+            assert!(!Vector2::from([Float::nan(), 1.0]).is_finite());
+            assert!(!Vector2::from([1.0, Float::infinity()]).is_finite());
+            assert!(Vector2::from([-1.0, 1.0]).is_finite());
+        }
     }
 
     mod vector3 {
@@ -1428,6 +1443,14 @@ mod tests {
                 assert_eq!(v, &VECTOR3);
             }
         }
+
+        #[test]
+        fn test_is_finite() {
+            use num_traits::Float;
+            assert!(!Vector3::from([Float::nan(), 1.0, 1.0]).is_finite());
+            assert!(!Vector3::from([1.0, 1.0, Float::infinity()]).is_finite());
+            assert!(Vector3::from([-1.0, 1.0, 1.0]).is_finite());
+        }
     }
 
     mod vector4 {
@@ -1539,5 +1562,13 @@ mod tests {
                 assert_eq!(v, &VECTOR4);
             }
         }
+
+        #[test]
+        fn test_is_finite() {
+            use num_traits::Float;
+            assert!(!Vector4::from([0.0, Float::nan(), 1.0, 1.0]).is_finite());
+            assert!(!Vector4::from([1.0, 1.0, Float::neg_infinity(), 0.0]).is_finite());
+            assert!(Vector4::from([-1.0, 0.0, 1.0, 1.0]).is_finite());
+        }
     }
 }