BCOR v1.1 file format
Header
SNP identifiers from Z file (sequence of NSNPs blocks)
SNP correlations (sequence of NSNPs × (1 + NSNPs) / 2 - NSNPs values)
| Bytes | Description |
| 7 | Magic number (bcor1.1) |
| 8 | Unsigned integer indicating the size SBCOR_file of the BCOR file in bytes |
| 4 | Unsigned integer indicating the number of samples NSamples used to compute SNP correlations in the BCOR file |
| 4 | Unsigned integer indicating the number of SNPs NSNPs for which correlations are available in the BCOR file |
| 1 | Unsigned integer representing the compression level Clevel used in the BCOR file |
| Clevel = 0 indicates 2 bytes | |
| Clevel = 1 indicates 4 bytes | |
| Clevel = 2 indicates 8 bytes | |
| Clevel = 3 indicates 1 byte | |
| 8 | Unsigned integer indicating the start position of the SNP correlations in the BCOR file |
| Bytes | Description |
| 4 | Unsigned integer indicating the length LBlock of the SNP identifier block in bytes |
| 4 | Unsigned integer indicating the line in which the SNP appears in the Z file |
| 2 | Unsigned integer indicating the length Lrsid of the entry in column rsid of the Z file in bytes |
| Lrsid | Entry in column rsid of the Z file |
| 4 | Unsigned integer indicating the entry in column position of the Z file |
| 2 | Unsigned integer indicating the length Lchromosome of the entry in column chromosome of the Z file in bytes |
| Lchromosome | Entry in column chromosome of the Z file |
| 4 | Unsigned integer indicating the length Lallele1 of the entry in column allele1 of the Z file in bytes |
| Lallele1 | Entry in column allele1 of the Z file |
| 4 | Unsigned integer indicating the length Lallele2 of the entry in column allele2 of the Z file in bytes |
| Lallele2 | Entry in column allele2 of the Z file |
| LBlock = 20 + Lrsid + Lchromosome + Lallele1 + Lallele2 number of bytes for the SNP identifier block | |
| Bytes | Description | |
| See Clevel for the number of bytes Nbytes | Unsigned integer y representing a correlation value in integer format | |
| Missing values are coded as follows | ||
| y = 53248 | if Clevel = 0 | |
| y = 3489660928 | if Clevel = 1 | |
| y = 14987979559889010688 | if Clevel = 2 | |
| y = 208 | if Clevel = 3 | |
| Convert a correlation value from integer format to floating-point format with the following transformation | ||
| x = 2(2 - 8 × Nbytes ) × y - 1 | ||