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Operations

add
Add multiple numbers together. The input ports allow multiple wires, which are all summed. If an input port is unwired, it is equivalent to setting it to zero.

subtract
Subtract two numbers. The input ports allow multiple wires, which are summed prior to the subtraction being carried out. If an input port is unwired, it is equivalent to setting it to zero. Note the small `+' and `-' signs on the input port indicating which terms are aded or subtracted from the result.

multiply
Multiple numbers with each other. The input ports allow multiple wires, which are all multiplied together. If an input port is unwired, it is equivalent to setting it to one.

divide
Divide a number by another. The input ports allow multiple wires, which are multiplied together prior to the division being carried out. If an input port is unwired, it is equivalent to setting it to one. Note the small `×' and `÷' signs indicating which port refers to the numerator and which the denominator.

pow
Raise one number to the power of another. The ports are labelled $x$ and $y$, referring the the formula $x^y$.

log
Take the logarithm of the $x$ input port, to base $b$. The base $b$ needs to be specified -- if the natural logarithm is desired ($b=e$), use the ln operator instead.

time
Returns the current value of system time.

copy
This just copies its input to its output, which is redundant on wiring diagrams, but is needed for internal purposes.

integrate
Creates an integration (or stock) variable. Editable attributes include the variable's name and its initial value at $t=0$.

data
A data interpolation widget. Currently, the data must be imported from a file containing two values on each line, eg:
0.1 0.3
0.5 0.7
0.9 1
If the input is less than the minimum key value (0.1 here), then the operation outputs the corresponding value (0.3). Similarly if the input is greater than the maximum (0.9), the corresponding value (1) is output. If it lies in between two keys (eg 0.2), the the output is linearly interpolated (0.4).

More formally, a data block is an empirical function, based on a table of pairs of values ( $x_i, y_i, i=1\ldots n, x_{i+1}>x_i$) read in from a file. The function's output is linearly interpolated from the data, ie:

\begin{displaymath}
f(x) = \left\{
\begin{array}{cl}
y_1 & x\leq x_1\\
y_n & x\...
...}{x_{i+1}-x_i} & x_i \leq x \leq
x_{i+1}\\
\end{array}\right.
\end{displaymath}

sqrt
Square root of the input

exp
Exponential of the input

ln
Natural logarithm

sin
sine function
cos
cosine function
tan
tangent function
asin
Arc sine, inverse of sine
acos
Arc cosine, inverse of cosine
atan
Arc tangent, inverse of tangent
sinh
hyperbolic sine function $\frac{e^x-e^{-x}}2$
cosh
hyperbolic cosine function $\frac{e^x+e^{-x}}2$
tanh
hyperbolic tangent function $\frac{e^x-e^{-x}}{e^x+e^{-x}}$


next up previous
Next: Variables Up: Reference Previous: Reference
Russell Standish 2014-11-16