reciprocal

reciprocal(X)

Return element-by-element reciprocal of X. The data type of the result is always DOUBLE.

DolphinDB's reciprocal and NumPy's numpy.reciprocal are mathematically equivalent, but they handle integer inputs differently. NumPy preserves the integer dtype, so 1/2 evaluates to 0; whereas DolphinDB automatically performs floating-point computation and returns 0.5. For example, In Dolphindb, reciprocal([1,2, 4]) returns [1,0.5,0.25], while np.reciprocal([1, 2, 4]) returns [1,0,0]. If NumPy uses floating-point input data, its result is consistent with DolphinDB.

X is a scalar/vector/matrix.

reciprocal(10);
// output: 0.1

reciprocal(1 2 4 8);
// output: [1,0.5,0.25,0.125]

reciprocal(1 2 4 8$2:2);