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See the recommended documentation of this function

Scilab help >> Xcos > palettes > Math operations palette > SUMMATION

# SUMMATION

### Description

This block performs addition or subtraction on scalar, vector or matrix inputs. The input datatype is set with the Datatype parameter. The Number of inputs or sign vector parameter defines the number of inputs and operation. For a single vector's input the block collapse the elements of the vector. Vectors/matrices inputs must have the same size.

The behavior of the block is summarized in the following table :

 Number of inputs Operation Remarks One y = (+/-)u u is a scalar value and the block has the behavior of a unitary gain. One y = u[1]+u[2]+...+u[N] u is a vector or a matrix and the block output is the sum of the elements of the input vector or matrix. Two or more y = k[1]*u1+k[2]*u2+...+k[N]*uN k is the scalar or vector value write in the Number of inputs or sign vector parameter. For the addition of all inputs, simply set this parameter to the number of inputs. To add/subtract the input ui, set in this parameter a vector k with k[i] = +1 (addition) or -1 (subtraction) for the input ui.

With integer input, on overflow the result can take different forms:

1- A normal non saturated result. By example, if type is int8 and the result 128, the block output value will be -128.

2- A saturated result. For the previous example the block output value will be 127.

3- An error message warning the user about the overflow.

The user can select one of these three forms by setting the Do on Overflow field to 0,1 or 2.

### Dialog box

• Datatype (1=real double 2=complex 3=int32 ...)

It indicates the type of the input/output data. It support all datatype, number must be between 1 and 8.

Properties : Type 'vec' of size 1.

• Number of inputs or sign vector (of +1,-1)

It indicates the number of inputs and the operation see the description for more detail. If you set a value other of -1 or +1, you get an error message box.

Properties : Type 'vec' of size -1.

• Do on Overflow(0=Nothing 1=Saturate 2=Error)

When this parameter is set to zero the result is similar to a normal summation of two integer matrix. When it is set to 1, on overflow the block saturate the result. When it is set to 2, on overflow an error message box appears. If the Data type is double or complex this parameter is not used.

Properties : Type 'vec' of size 1.

### Default properties

• always active: no

• direct-feedthrough: yes

• zero-crossing: no

• mode: no

• regular inputs:

- port 1 : size [-1,-2] / type 1

- port 2 : size [-1,-2] / type 1

• regular outputs:

- port 1 : size [-1,-2] / type 1

• number/sizes of activation inputs: 0

• number/sizes of activation outputs: 0

• continuous-time state: no

• discrete-time state: no

• object discrete-time state: no

• name of computational function: summation

### Interfacing function

• SCI/modules/scicos_blocks/macros/Linear/SUMMATION.sci

### Computational function

• SCI/modules/scicos_blocks/src/c/summation.c

• SCI/modules/scicos_blocks/src/c/summation_z.c

• SCI/modules/scicos_blocks/src/c/summation_i32n.c

• SCI/modules/scicos_blocks/src/c/summation_i16n.c

• SCI/modules/scicos_blocks/src/c/summation_i8n.c

• SCI/modules/scicos_blocks/src/c/summation_ui32n.c

• SCI/modules/scicos_blocks/src/c/summation_ui16n.c

• SCI/modules/scicos_blocks/src/c/summation_ui8n.c

• SCI/modules/scicos_blocks/src/c/summation_i32s.c

• SCI/modules/scicos_blocks/src/c/summation_i16s.c

• SCI/modules/scicos_blocks/src/c/summation_i8s.c

• SCI/modules/scicos_blocks/src/c/summation_ui32s.c

• SCI/modules/scicos_blocks/src/c/summation_ui16s.c

• SCI/modules/scicos_blocks/src/c/summation_ui8s.c

• SCI/modules/scicos_blocks/src/c/summation_i32e.c

• SCI/modules/scicos_blocks/src/c/summation_i16e.c

• SCI/modules/scicos_blocks/src/c/summation_i8e.c

• SCI/modules/scicos_blocks/src/c/summation_ui32e.c

• SCI/modules/scicos_blocks/src/c/summation_ui16e.c

• SCI/modules/scicos_blocks/src/c/summation_ui8e.c

### Authors

• Alan Layec INRIA

• Ramine Nikoukhah INRIA