eldo_user

Monte Carlo Analysis
How to Specify a Distribution Function
.DISTRIB TRI (0, 0) (0.66666, 1) (1, 0)
.PARAM XVAL=5 LOT/TRI=15
V1 1 0 XVAL
.OP
.MC 1000 NBBINS=50
.EXTRACT DC LABEL=R1 E(V1,V)
.END
The distribution parameters a, b are defined implicitly by construction. The most frequent value
m is obtained by the formula: 5 × 0.66666 + 5 ≈ 15. Note also that the value XVAL=5 in the
PARAM statement cannot be considered as the nominal value of the resistor. It is used as a shift
in value of XVAL and LOT/TRI=15 is a scaling factor.
Other Common Distributions
You can generate additional distributions by using the basic building blocks of the previous
section.
• Half-Normal Distribution
The half-normal distribution is the probability of the absolute value of a normal
distribution with mean 0 and variance σ 2 . If X ~ N(0, σ 2 ), then Y = |X| is half-normally
distributed.
• Log-Normal Distribution
The log-normal distribution is the single-tailed probability distribution of any random
variable whose logarithm is normally distributed. If X is a random variable with a
normal distribution, then Y = e X has a log-normal distribution.
Related Topics
Tip
See “.DISTRIB” in the Eldo Reference Manual.
Correlation Between Gaussian Input Variables
Specifying a Monte Carlo Analysis
436
Eldo® User's Manual, 15.3