If the participant’s name is `MySolver`

, preCICE creates the following files:

## precice-MySolver-iterations.log

Information per time window with number of coupling iterations etc. (only for implicit coupling). In case you use a quasi-Newton acceleration, this file also contains information on the state of the quasi-Newton system.

An example file:

**Version:**Starting from preCICE version 2.3.0, the formatting of the numbers in these log files changed from an arbitrary to a fixed column width.

```
TimeWindow TotalIterations Iterations Convergence QNColumns DeletedQNColumns DroppedQNColumns
1 5 5 1 0 0 0
2 10 5 1 0 0 0
3 15 5 1 0 0 0
4 20 5 1 0 0 0
5 24 4 1 0 0 0
6 28 4 1 0 0 0
7 32 4 1 0 0 0
...
```

`TimeWindow`

is the time window counter.`TotalIterations`

is the total (summed up) number of coupling iterations.`Iterations`

is the number of iterations preCICE used in each time window.`Convergence`

indicates whether the coupling converged (`1`

) or not (`0`

) in each time window.`QNColumns`

gives the amount of columns in the tall-and-skinny matrices V and W after convergence.`DeletedQNColumns`

gives the amount of columns that were filtered out during this time window (due to a QR filter). In this example no columns were filtered out.`DroppedQNColumns`

gives the amount of columns that went out of scope during this time window (due to`max-iterations`

or`time-windows-reused`

). Here, for example, 5 columns went out of scope during the 6th time window.

Further reading: quasi-Newton configuration.

## precice-MySolver-convergence.log

Information per iteration with current residuals (only for `second`

participant in an implicit coupling).

An example file:

**Version:**Starting from preCICE version 2.3.0, the formatting of the numbers in these log files changed from a decimal to a fixed scientific format.

```
TimeWindow Iteration ResRel(Temperature) ResRel(Heat-Flux)
1 1 1.00000000e+00 1.00000000e+00
1 2 2.36081866e-03 4.61532554e-01
1 3 1.76770050e-03 2.20718535e-03
1 4 8.24839318e-06 4.83731693e-04
1 5 1.38649284e-06 3.03987119e-05
2 1 2.02680329e-03 1.14463674e+00
2 2 1.10152875e-03 4.53255279e-01
...
```

`TimeWindow`

is the time window counter.`Iteration`

is the coupling iteration counter within each time window. So, in the first time window, 6 iterations were necessary to converge, in the second time window 3.- And then two convergence measure are defined in the example. Two relative ones – hence the
`...Rel(...)`

. The two columns`ResRel(Temperature)`

and`RelRel(Force)`

give the relative residual for temperature and heat flux, respectively, at the start of each iteration.

## precice-MySolver-events.json

Recorded events with timestamps. See page on performance analysis.

## precice-MySolver-events-summary.log

Summary of all events timings. See page on performance analysis.

## precice-postProcessingInfo.log

Advanced information on the numerical performance of the Quasi-Newton coupling (if used and enabled)

**Version:**In preCICE v1.3.0 and earlier, instead of

`precice-MySolver-events.json`

, two performance output files were used: `precice-MySolver-events.log`

and `precice-MySolver-eventTimings.log`

.
**Version:**In preCICE v1.2.0 and earlier, slightly different names were used:

`iterations-MySolver.txt`

,`convergence-MySolver.txt`

, `Events-MySolver.log`

,`EventTimings-MySolver.log`

, and `postProcessingInfo.txt`

.