Running MemExp

MemExp produces detailed graphical summaries of both the MEM and NLS/ML calculations, but it is not run interactively via a graphical user interface. Instead, input to MemExp is defined in one or more files specified on the command line (except in simple mode) executed to run the program. This command-line interface provides a convenient way to analyze many kinetics traces in the same way. In addition, the input parameter files represent a record of the analysis for future reference. Similarly, because of the multiple arguments passed to MemExp on the command line, it is convenient to create a command file, e.g., memexp.com (or memexp.bat for Windows), in which each line represents a MemExp run. Thus, several data sets can be analyzed with a single command, e.g., ./memexp.com (or @memexp for Windows). Under Windows, the batch file can also be run by right-clicking on it to "open" it.

MemExp can be invoked in one of five modes: simple, auto, allin1, invert, or analysis. The first three do everything, all in one MemExp call, beginning with one (simple and auto) or more (allin1) MEM inversions of data using uniform error estimates, and then inverting the data using the estimated time-dependent standard errors in the mean. The invert mode simply inverts a data set once, and the analysis mode analyzes a previously obtained MEM distribution and its corresponding fit to the data.

Recommendation: First, try MemExp in simple mode. To change the parameter values assumed in simple mode, the files data_file.mem and data_file.ana output in simple mode can be edited for a second analysis using auto mode. Use of allin1 mode may be necessary if the standard errors are to be estimated, and the two estimates obtained in auto mode haven't converged satisfactorily.

Recommendation: MemExp is best used to interpret raw (unaveraged) kinetics data. Baseline drifts and any other systematic errors in the data can be more difficult to account for quantitatively if multiple data files are averaged together before analyzing using MemExp.

Recommendation: Because MemExp generates several files, it's convenient to place each raw data file in its own subdirectory before analyzing it with MemExp.

Recommendation: In most cases, it should be advantageous to set IBIGF = 3 and LTCUT to a value of log $\tau$ that excludes the short-lifetime peaks that may appear with a uniform prior (as in example 4 below). However, for kinetics with both sharp and broad phases, consider IBIGF = 1 and 'differential blurring' (as in example 2 below).