The REPLICATE_INPLACE procedure updates an existing array by replacing all or selected parts of it with a specified value. REPLICATE_INPLACE can be faster and use less memory than the IDL function REPLICATE or the IDL array notation for large arrays that already exist.

*Note: *REPLICATE_INPLACE is much faster when operating on entire arrays and rows, than when used on columns or higher dimensions.

## Examples

; Create a multidimensional zero array:

A = FLTARR( 40, 90, 10)

; Populate it with the value 4.5. (i.e., A[*]= 4.5 ):

REPLICATE_INPLACE, A, 4.5

;Update a single subvector.(i.e., A[*,4,0]= 20. ):

REPLICATE_INPLACE, A, 20, 1, [0,4,0]

; Update a group of subvectors.(i.e.,

; A[0,0,*] = -8

; A[0,5,*] = -8

; A[0,89,*] = -8 )

REPLICATE_INPLACE, A, -8, 3, [0,0,0], 2, [0,5,89]

; Update a 2-dimensional slice of A (i.e., A[9,*, *] = 0.):

REPLICATE_INPLACE, A, 0., 3, [9,0,0] , 2, LINDGEN(90)

## Syntax

REPLICATE_INPLACE, *Array*,* Value *[, *D1*,* Loc1 *[, *D2*,* Range*]]

## Arguments

### Array

The array to be updated. *Array *can be of any numeric type. REPLICATE_INPLACE does not change the size or type of *Array*.

### Value

The value which will fill all or part of *Array*. *Value* may be any scalar or one-element array that IDL can convert to the type of *Array*. REPLICATE_INPLACE does not change *Value*.

### D1

An integer indicating which dimension of *Array *is to be updated. All of the values changed will be in dimension *D1*.

*Note: *The *D1* parameter is a one-based index; that is, the first dimension of the array is dimension 1, not dimension 0.

### Loc1

An array with the same number of elements as the number of dimensions of *Array*. The *Loc1 *and *D1* arguments together determine which one-dimensional subvector (or subvectors, if *D2* and *Range* are provided) of *Array *is to be updated. The element of *Loc1* that corresponds to the value of *D1* is ignored.

For example, suppose you have a three-dimensional array of data. To update all elements in the subvector described by array[*,0,0]:

array = FLTARR(5,5,5)

REPLICATE_INPLACE, array, 98.6, 1, [0,0,0]

To change the same values using array syntax:

array[*,0,0] = 98.6

### D2

An integer indicating in which dimension of *Array *a group of one-dimensional subvectors are to be updated. *D2* should be different from *D1*. If *D2* is present, the element of *Loc1* that corresponds to the value of *D2* is ignored.

*Note: *The *D2* parameter is a one-based index; that is, the first dimension of the array is dimension 1, not dimension 0.

### Range

An array of indices into dimension *D2* of *Array*, indicating where to put one-dimensional updates of *Array*.

For example, suppose you have a three-dimensional array of data. To update all elements in the subvector described byarray[2,1:2,*]:

array = FLTARR(5,5,5)

REPLICATE_INPLACE, array, 3.14, 3, [2,0,0], 2, [1,2]

To change the same values using array syntax:

array[2,1:2,*] = 3.14

## Keywords

### Thread Pool Keywords

This routine is written to make use of IDL’s *thread pool*, which can increase execution speed on systems with multiple CPUs. The values stored in the !CPU system variable control whether IDL uses the thread pool for a given computation. In addition, you can use the thread pool keywords TPOOL_MAX_ELTS, TPOOL_MIN_ELTS, and TPOOL_NOTHREAD to override the defaults established by !CPU for a single invocation of this routine. See Thread Pool Keywords for details.

## Version History

5.1 |
Introduced |