Trying to translate BASIC code written in the 1990's to Python. I keep coming across two symbols, ! (exclamation mark) and . (period). I can't find any documentation online on what they do.
I have the code running but some of the outputs are not as expected - I am wondering if these might be the issue as I previously thought that the period may just be a typo for a multiplication.
Examples:
|
v
QWLOST = (((TW-TDAO)/(TWRT-TDAOR))^1.25)*((VISR/VIS)^0.25).(PW+PE)*DT
TFAVE = (TTO+TBO)/2!
^
|
In case anyone else in the future needs to know this.
! - defines a single
. - Was just a typo for * (multiplication)
I tried a few things in bwBasic (in Linux, in case that's relevant!).
bwBASIC: list
10: for i = 1 to 20
20: print i, ., . - i
30: next i
40: print ".="; .
This gave me:
bwBASIC: run
1 20 19
2 20 18
3 20 17
4 20 16
5 20 15
6 20 14
7 20 13
8 20 12
9 20 11
10 20 10
11 20 9
12 20 8
13 20 7
14 20 6
15 20 5
16 20 4
17 20 3
18 20 2
19 20 1
20 20 0
.= 20
Which would suggest that . (in bwBasic in any case) is the max number in a for loop.
Currently for a task, I am working with input files which give Matrix related test cases (Matrix Multiplication) i.e., example of an input file ->
N M
1 3 5 ... 6 (M columns)
....
5 4 2 ... 1 (N rows)
I was using simple read() to access them till now, but this is not efficient for large files of size > 10^2.
So I wanted to know is there some way to use processes to do this in parallel.
Also I was thinking of using multiple IO readers based on line, so then each process could read different segments of the file but couldn't find any helpful resources.
Thank you.
PS: Current code is using this:
io:fread(IoDev, "", "~d")
Did you consider to use re module? I did not make a performance test, but it may be efficient. In the following example I do not use the first "M N" line. So I did not put it in the matrix.txt file.
matrix file:
1 2 3 4 5 6 7 8 9
11 12 13 14 15 16 17 18 19
21 22 23 24 25 26 27 28 29
31 32 33 34 35 36 37 38 39
I made the conversion in the shell
1> {ok,B} = file:read_file("matrix.txt"). % read the complete file and store it in a binary
{ok,<<"1 2 3 4 5 6 7 8 9\r\n11 12 13 14 15 16 17 18 19\r\n21 22 23 24 25 26 27 28 29\r\n31 32 33 34 35 36 37 38 39">>}
2> {ok,ML} = re:compile("[\r\n]+"). % to split the complete binary in a list a binary, one for each line
{ok,{re_pattern,0,0,0,
<<69,82,67,80,105,0,0,0,0,0,0,0,1,8,0,0,255,255,255,255,
255,255,...>>}}
3> {ok,MN} = re:compile("[ ]+"). % to split the line into binaries one for each integer
{ok,{re_pattern,0,0,0,
<<69,82,67,80,73,0,0,0,0,0,0,0,17,0,0,0,255,255,255,255,
255,255,...>>}}
4> % a function to split a line and convert each chunk into integer
4> F = fun(Line) -> Nums = re:split(Line,MN), [binary_to_integer(N) || N <- Nums] end.
#Fun<erl_eval.7.126501267>
5> Lines = re:split(B,ML). % split the file into lines
[<<"1 2 3 4 5 6 7 8 9">>,<<"11 12 13 14 15 16 17 18 19">>,
<<"21 22 23 24 25 26 27 28 29">>,
<<"31 32 33 34 35 36 37 38 39">>]
6> lists:map(F,Lines). % map the function to each lines
[[1,2,3,4,5,6,7,8,9],
[11,12,13,14,15,16,17,18,19],
[21,22,23,24,25,26,27,28,29],
[31,32,33,34,35,36,37,38,39]]
7>
if you want to check the matrix size, you can replace the last line with:
[[NbRows,NbCols]|Matrix] = lists:map(F,Lines),
case (length(Matrix) == NbRows) andalso
lists:foldl(fun(X,Acc) -> Acc andalso (length(X) == NbCols) end,true,Matrix) of
true -> {ok,Matrix};
_ -> {error_size,Matrix}
end.
is there some way to use processes to do this in parallel.
Of course.
Also I was thinking of using multiple IO readers based on line, so
then each process could read different segments of the file but
couldn't find any helpful resources.
You don't seek to positions in a file by line, rather you seek to byte positions. While a file may look like a bunch of lines, a file is actually just one long sequence of characters. Therefore, you will need to figure out what byte positions you want to seek to in the file.
Check out file:position, file:pread.
I have this data in Excel.
A B C
--------------------------------------
Line Number Value #1 Value #2
1 21 35
2 21 27
3 21 18
4 10 47
5 50 5
6 37 68
7 10 21
8 75 21
I tried to calculate the total "21" based on odd line number. In this situation, the answer should be 3. However, neither" IF(MOD(A1:A8,2)=1,COUNTIF(B1:C8,21)) " nor " {IF(MOD(A1:A8,2)=1,COUNTIF(B1:C8,21))} "worked and Google didn't yield anything helpful. Could anyone help me? Thanks!!
This works for odd lines:
=SUM(COUNTIF(A:B,21)-SUMPRODUCT((A:B=21)*(MOD(ROW(A:B),2)=0)))
there may be a better way of writing this formula.
Use this to count even lines:
=SUMPRODUCT((A:B=21)*(MOD(ROW(A:B),2)=0))
Are there an efficient algorithm to search and dump all common substrings (which length is 3 or longer) between 2 strings?
Example input:
Length : 0 5 10 15 20 25 30
String 1 : ABC-DEF-GHI-JKL-ABC-ABC-STU-MWX-Y
String 2 : ABC-JKL-MNO-ABC-DEF-PQR-DEF-ZWX-Y
Example output:
In string 1 2
---------------------------
ABC-DEF 0 12
ABC-DE 0 12
BC-DEF 1 13
:
-ABC- 15,19 11
-JKL- 11 3
-DEF- 3 15
-JKL 11 3
JKL- 12 4
-DEF 3 15,23
DEF- 4 16
WX-Y 29 29
ABC- 0,16,20 0,12
-ABC 15,19 11
DEF- 4 16,24
DEF 4 16,24
ABC 0,16,20 0,12
JKL 12 4
WX- 29 29
X-Y 30 30
-AB 15,19 11
BC- 1,17,21 1,13
-DE 3 15,23
EF- 5 17,25
-JK 11 3
KL- 13 5
:
In the example, "-D", "-M" is also a common substring but is not required, because it's length is only 2. (There might be some missing outputs in example because there are so many of them...)
You can find all common substrings using a data structure called a Generalized suffix tree
Libstree contains some example code for finding the longest common substring. That example code can be modified to obtain all common substrings.
I have written a program which generates parameter index for 2 variables. Say, a and b in steps of 5. like this I have to do for 23 variables. So I don't want to write 23 for-loops to run, how can I make it into a single for-loop which is common for all 23 variables. I hope it can be done with an array, but i don't know how to implement it via program.
Could you please help me?
Program:
int z, p
float a, b
float a0, an, s, a1, b0, bn, b1
str var
s=5; a0=1; an=10; b0=8; bn=13 // s= steps, a0, b0= initial value, an,bn=final value
z=0
a1=(an-a0)/s
b1=(bn-b0)/s
for (a=(a1+a0);a<=an;a=a+a1)
for (b=(b1+b0);b<=bn;b=b+b1)
echo {z} {a} {b} -format "%25s" >> /home/genesis/genesis-2.3/genesis/Scripts/kinetikit/dhanu19.txt
z=z+1
end
end
output : dhanu19.txt
0 2.8 9
1 2.8 10
2 2.8 11
3 2.8 12
4 2.8 13
5 4.6 9
6 4.6 10
7 4.6 11
8 4.6 12
9 4.6 13
10 6.4 9
11 6.4 10
12 6.4 11
13 6.4 12
14 6.4 13
15 8.2 9
16 8.2 10
17 8.2 11
18 8.2 12
19 8.2 13
20 10 9
21 10 10
22 10 11
23 10 12
24 10 13
Have you considered writing either a script or a program to write the script for you? Generating shell-scripts, then running them can sometimes be a powerful solution to problems.
Which Shell are you referring to? Declaring Arrays has some syntactical differences between zsh, bash or so...
Let's assume you write the 23 for loop.
If you have 5 steps for each loop, you will end up with 5^23 parameter !
Let's suppose each loop outputs 1 byte, you still need to store something like 10^16 bytes, or ten thousand terabytes.
I think you should reconsider your problem, or reformulate your question
Edit :
This is not a forums (and aven in forums you can edit your post).
Please edit your question instead of posting new answer, I think it is interesting