5.1.3.6. Example: Using variables as test values¶
Description: A simple example showing the behaviour when a reset test value is given by a variable.
Note that:
all elements are in the same component;
the order values of resets are not shown; and
all variables have dimensionless units.
component:
├─ math:
│ └─ ode(A, t) = 1
│
├─ variable: A initially 1
│
└─ variable: B initially 2
└─ reset:
├─ when B == A
└─ then B = B + 1
See CellML syntax
<variable name="t" units="dimensionless" />
<variable name="A" units="dimensionless" initial_value="1" />
<variable name="B" units="dimensionless" initial_value="2" />
<math>
<apply><eq/>
<diff>
<ci>B</ci>
<bvar>t</bvar>
</diff>
<cn cellml:units="dimensionless">1</cn>
</apply>
</math>
<reset variable="B" test_variable="B">
<test_value>
<ci>A</ci>
</test_value>
<!-- Variable B is given a value of B+1 when B equals A. -->
<reset_value>
<apply><plus/>
<ci>B</ci>
<cn cellml:units="dimensionless">1</cn>
</apply>
</reset_value>
</reset>
At t = 1 the following situation occurs:
t |
0 |
0.1 |
… |
1 |
A |
1 |
1.1 |
… |
2 |
B |
2 |
2 |
… |
2 |
The reset for B is now active, leading to the following update:
t |
0 |
0.1 |
… |
1 |
A |
1 |
1.1 |
… |
2 |
B |
2 |
2 |
… |
2 → 3 |
A change has been made, so a second cycle of evaluations is started. No resets are found to be active (B no longer equals A), and so model dynamics continue.
t |
0 |
0.1 |
… |
1 |
1.1 |
… |
2 |
2.1 |
A |
1 |
1.1 |
… |
2 |
2.1 |
… |
3 |
3.1 |
B |
2 |
2 |
… |
2 → 3 |
3 |
3 |
3 → 4 |
4 |
At t = 2 the reset rule is triggered a second time, in a similar fashion.
