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jc_0805: Numerical operation block inputs

Sub ID Recommendations

  • NA-MAAB — a1/a2, b, c1/c2, d, e, f1/f2, g, h, i, j

  • JMAAB — a1/a2, b, c1/c2, d, e, f1/f2, g, h, i, j

MATLAB Versions

All

Rule

Sub ID a1

When using and Abs block with signed integer types, the input shall not be the most negative value.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID a2

Abs block parameter Saturation on Integer Overflow shall be selected.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID b

Input to the Abs block shall not be unsigned integer types or fixed-point types.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID c1

Input to the Sqrt block shall not be a negative value.

Custom Parameter

Not Applicable

Example — Correct

Negative number is saturated with 0.

Simulation result

Example — Incorrect

Sub ID c2

Sqrt block parameter Output Signal Type shall be set to complex.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID d

Input to the Reciprocal Sqrt block shall not be less than zero.

Custom Parameter

Not Applicable

Example — Correct

Less than eps saturated with eps.

Simulation result: Plot as Y=log10(Z)

Example — Incorrect

Sub ID e

When Math Function block parameter Function is set to log or log10, the input to the block shall not be zero.

Custom Parameter

Not Applicable

Example — Correct

Replace within ±eps with ±eps

Simulation result: Plot as Y = |Z|

Example — Incorrect

Sub ID f1

When Math Function block parameter Function is set to log or log10, the input to the block shall not be a negative number.

Custom Parameter

Not Applicable

Example — Correct

When the input is less than eps, the value is saturated to eps. Less than eps saturated with eps.

Simulation result

Example — Incorrect

Sub ID f2

When Math Function block parameter Function is set to log or log10, block parameter Output Signal Type shall be set to complex.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID g

When Math Function block parameter Function is set to mod or rem, the second argument input shall not be zero.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID h

When Math Function block parameter Function is set to reciprocal, the input to the block shall not be zero.

Custom Parameter

Not Applicable

Example — Correct

Replace within ±eps with ±eps

Simulation result: Simulation results is not inf, but since it is close to zero, the change in the output value is significant.

Example — Incorrect

Sub ID i

When Product block parameter Multiplication is set to Element-wise(.*), the divisor input shall not be zero.

Note

To specify a divisor input, set Product block parameter Number of inputs to */.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Sub ID j

When Product block parameter Multiplication is set to Matrix(*), the divisor input shall not be set to a singular matrix.

Note

To specify a divisor input, set Product block parameter Number of inputs to */.

Custom Parameter

Not Applicable

Example — Correct

Example — Incorrect

Rationale

Sub IDs a1, c1, d, e, f1, g, h, i, j:

  • The result of entering an invalid value is implementation dependent. Deviation from the rules can result in unintended behavior.

Sub ID a2:

  • Correct settings prevent unintended behavior that can result from using invalid values.

Sub ID b:

  • The block can become optimized out of the generated code, resulting in a block that you cannot trace to the generated code.

Sub IDs c2, f2:

  • Correct settings prevent unintended behavior that can result from using negative values.

Verification

Adherence to this modeling guideline cannot be verified by using a Model Advisor check.

Last Changed

R2020a

See Also

Introduced in R2020a