perctl - computation of percentils

### Calling Sequence

  `=perctl(x,y)`

### Parameters

- `x` : real or complex vector or matrix
- `y` : vector of positif values between 0 and 100.

### Description

Compute the matrix p of percentils (in increasing order, column first) of the real vector or matrix x indicated by the entries of y, the values of entries of y must be positive integers between 0 and 100. p is a matrix whose type is length(y) x 2 and the content of its first column are the percentils values. The contents of its second column are the places of the computed percentiles in the input matrix x.

### Examples

    x=[6 7 0 7 10 4 2 2 7 1;
       6 0 5 5 5 2 0 6 8 10;
       8 6 4 3 5 9 8 3 4 7;
       1 3 2 7 6 1 1 4 8 2;
       6 3 5 1 6 5 9 9 5 5;
       1 6 4 4 5 4 0 8 1 8;
       7 1 3 7 8 0 2 8 10 8;
       3 6 1 9 8 5 5 3 2 1;
       5 7 6 2 10 8 7 4 0 8;
       10 3 3 4 8 6 9 4 8 3]
    y=[10 20 30]
    p=perctl(x,y)

### Author

Carlos Klimann

### Bibliography

HYNDMAN,Rob J. and FAN Yanan, Sample Quantiles in Statistical Packages, The American Statistician, Nov.1996, Vol 50, No.4