Delta software helps users reduce files of interest by testing their level of interestingness.
Delta project is a useful software tool that helps users minimize "interesting" files based on a test of their "interestingness". It is especially useful in situations where one needs to isolate a small failure-inducing substring of a large input that causes a program to exhibit a bug.
To better understand how to use Delta, it is helpful to look at an example of its usage. Simon Goldsmith has helpfully provided an example, which is described in Using Delta, a more detailed document that describes each tool.
One key feature of Delta is its ability to do a controlled experiment. In the example Simon provides, Delta doesn't just minimize a file that causes Oink to produce an error message, but rather it minimizes a file that causes gcc to accept AND oink to reject in a specific way. This is a controlled experiment, where gcc serves as the control. First-time users should be careful not to ignore this aspect of the problem.
Another important feature of Delta is its ability to exploit nested structure. Although some files may have simpler syntax than C++, most languages have some nested structure. Delta filters input through the topformflat utility to suppress any newlines past a particular nesting depth, which explains the nesting structure. If your language has a different nesting structure than C/C++, you can write your own multidelta and substitute it.
In this new release of Delta, it is much easier to stop the program. Delta now catches signals and distinguishes them from return codes. It also watches for the DELTA-STOP file at the same granularity as the tests are run. In multidelta, running the input file through cpp is off by default and can be turned on with the flag -cpp..
Overall, Delta is an impressive software tool that is highly recommended for users who need to minimize "interesting" files. With its features for controlled experimentation and nested structure exploitation, Delta is a great asset for anyone working with large input files.
To better understand how to use Delta, it is helpful to look at an example of its usage. Simon Goldsmith has helpfully provided an example, which is described in Using Delta, a more detailed document that describes each tool.
One key feature of Delta is its ability to do a controlled experiment. In the example Simon provides, Delta doesn't just minimize a file that causes Oink to produce an error message, but rather it minimizes a file that causes gcc to accept AND oink to reject in a specific way. This is a controlled experiment, where gcc serves as the control. First-time users should be careful not to ignore this aspect of the problem.
Another important feature of Delta is its ability to exploit nested structure. Although some files may have simpler syntax than C++, most languages have some nested structure. Delta filters input through the topformflat utility to suppress any newlines past a particular nesting depth, which explains the nesting structure. If your language has a different nesting structure than C/C++, you can write your own multidelta and substitute it.
In this new release of Delta, it is much easier to stop the program. Delta now catches signals and distinguishes them from return codes. It also watches for the DELTA-STOP file at the same granularity as the tests are run. In multidelta, running the input file through cpp is off by default and can be turned on with the flag -cpp..
Overall, Delta is an impressive software tool that is highly recommended for users who need to minimize "interesting" files. With its features for controlled experimentation and nested structure exploitation, Delta is a great asset for anyone working with large input files.
What's New
Version 2006.07.15: N/A