I have a variable that is defined as an int and wants to create a coverpoint for this variable but I want to ignore values greater than 16384. How can I do this?
I have tried two things that haven't worked.
int acl;
int acl;
acl: coverpoint (ccr_pkt.acl) {
ignore_bins acl = {[16384:$]};
}
acl :
coverpoint (ccr_pkt.acl) iff (ccr_pkt.acl < 16384) {
}
Neither have worked. There were still bins created for values of acl greater than 16384.
For 1), you need to specify bins to hit. As soon as you specify any kind of bin for a coverpoint, there are no implicit bins created.
For 2), iff does not control bin creation, it only affects sampling.
You should use:
acl: coverpoint (ccr_pkt.acl) {
bins b[] = {[0:16383]}; }
Related
What I want is extracting a value from vector using a variable scalar index.
Like _mm_extract_epi8 / _mm256_extract_epi8 but with non-immediate input.
(There are some results in the vector, the one with the given index is found out to be the true result, the rest are discarded)
Especially, if index is in a GPR, the easiest way is probably to store val to memory and then movzx it into another GPR. Sample implementation using C:
uint8_t extract_epu8var(__m256i val, int index) {
union {
__m256i m256;
uint8_t array[32];
} tmp;
tmp.m256 = val;
return tmp.array[index];
}
Godbolt translation (note that a lot of overhead happens for stack alignment -- if you don't have an aligned temporary storage area, you could just vmovdqu instead of vmovdqa): https://godbolt.org/z/Gj6Eadq9r
So far the best option seem to be using _mm_shuffle_epi8 for SSE
uint8_t extract_epu8var(__m128i val, int index) {
return (uint8_t)_mm_cvtsi128_si32(
_mm_shuffle_epi8(val, _mm_cvtsi32_si128(index)));
}
Unfortunately this does not scale well for AVX. vpshufb does not shuffle across lanes. There is a cross lane shuffle _mm256_permutevar8x32_epi32, but the resulting stuff seem to be complicated:
uint8_t extract_epu8var(__m256i val, int index) {
int index_low = index & 0x3;
int index_high = (index >> 2);
return (uint8_t)(_mm256_cvtsi256_si32(_mm256_permutevar8x32_epi32(
val, _mm256_zextsi128_si256(_mm_cvtsi32_si128(index_high))))
>> (index_low << 3));
}
I am receiving ROS message of type
sensor_msgs::PointCloud2ConstPtr
in my callback function then I transform it to pointer of type
pcl::PointCloud<pcl::PointXYZ>::Ptr
using function
pcl::fromROSMsg.
After that using this code from pcl tutorials for normal estimation:
void OrganizedCloudToNormals(
const pcl::PointCloud<pcl::PointXYZ>::Ptr &_inputCloud,
pcl::PointCloud<pcl::PointNormal>::Ptr &cloud_normals
)
{
pcl::console::print_highlight ("Estimating scene normals...\n");
pcl::NormalEstimationOMP<pcl::PointXYZ,pcl::PointNormal> nest;
nest.setRadiusSearch (0.001);
nest.setInputCloud (_inputCloud);
nest.compute (*cloud_normals);
//write 0 wherever is NaN as value
for(int i=0; i < cloud_normals->points.size(); i++)
{
cloud_normals->points.at(i).normal_x = isnan(cloud_normals->points.at(i).normal_x) ? 0 : cloud_normals->points.at(i).normal_x;
cloud_normals->points.at(i).normal_y = isnan(cloud_normals->points.at(i).normal_y) ? 0 : cloud_normals->points.at(i).normal_y;
cloud_normals->points.at(i).normal_z = isnan(cloud_normals->points.at(i).normal_z) ? 0 : cloud_normals->points.at(i).normal_z;
cloud_normals->points.at(i).curvature = isnan(cloud_normals->points.at(i).curvature) ? 0 : cloud_normals->points.at(i).curvature;
}
}
after that I have point cloud of the type pcl::PointNormal and trying to downsample it
const float leaf = 0.001f; //0.005f;
pcl::VoxelGrid<pcl::PointNormal> gridScene;
gridScene.setLeafSize(leaf, leaf, leaf);
gridScene.setInputCloud(_scene);
gridScene.filter(*_scene);
where _scene is of the type
pcl::PointCloud<pcl::PointNormal>::Ptr _scene (new pcl::PointCloud<pcl::PointNormal>);
then after filtering I end up with my point cloud _scene and it has only 1 point inside. I have tried to change leaf size but that doesn't change outcome.
Does anyone knows what am I doing wrong?
Thanks in advance
I have found where was the problem. Type pcl::PoinNormal has fields x,y,z,normal_x, normal_y and normal_z but in my function OrganizedCloudToNormals I filled only fields normal_x, normal_y and normal_z and fields x, y and z had value 0 for each point. When I filled fields x,y and z from input point cloud problem with filtering (downsampling) disappeared I have filtered cloud with more than 1 point inside. Probably lack of values in x,y and z fields caused problems later in filter method of the voxel grid object.
I am working with bitcoin source code want to set initial difficulty to 1 (I changed bdiff,nBits field). So I need to change pdiff as well. according to :
difficulty = difficulty_1_target / current_target (target is a 256
bit number)
difficulty_1_target can be different for various ways to measure
difficulty. Traditionally, it represents a hash where the leading 32
bits are zero and the rest are one (this is known as "pool difficulty"
or "pdiff"). The Bitcoin protocol represents targets as a custom
floating point type with limited precision; as a result, Bitcoin
clients often approximate difficulty based on this (this is known as
"bdiff").
Anyone knows where pdiff is stored ? Is it hard coded ?
I found the solution! It's not exactly a pdiff field in the code but there is a function in blockchain.cpp :
double GetDifficulty(const CBlockIndex* blockindex)
{
if (blockindex == nullptr)
{
return 1.0;
}
int nShift = (blockindex->nBits >> 24) & 0xff;
double dDiff =
(double)0x0000ffff / (double)(blockindex->nBits & 0x00ffffff);
while (nShift < 29)
{
dDiff *= 256.0;
nShift++;
}
while (nShift > 29)
{
dDiff /= 256.0;
nShift--;
}
return dDiff;
}
for bitcoin initial nBits is equal to 0x1d00ffff so dDiff field above becomes 1 and nshift is equal to 1D. For my private version I set nBits to 0x1f0fffff and should calculate dDiff like
double dDiff =(double)0x000ffff / (double)(blockindex->nBits & 0x00ffffff);
and nShift field for me is 0x1f so I changed while conditions to while(nShift < 31) andwhile (nShift > 31). by running command bitcoin-cli getdifficulty I got 1 as initial difficulty.
I have a Data object in swift that is an array of Int16 objects. For some reason using ".pcmFormatInt16" did not work for the format of my AVAudioPCMBuffer and yielded no sound, or a memory error. Eventually, I was able to get white noise/static to play from the speakers by converting the Int16 to a float and putting that onto both channels of my AVAudioPCMBuffer. I have a feeling that I am getting close to the answer, because whenever I speak into the microphone I hear a different frequency of static. I think the issue is that I am not converting the converted Int16 into the buffer floatChannelData.
Here is my code:
for ch in 0..<2 {
for i in 0..<audio.count {
var val = Float( Int16(audio[i]) ) / Float(Int16.max)
if( val > 1 ){
val = 1;
}
if( val < -1 ){
val = -1;
}
self.buffer.floatChannelData![ch][i+self.bufferCount] = val
self.bufferCount+=1
}
}
self.audioFilePlayer.scheduleBuffer(self.buffer, at:nil, options: .interruptsAtLoop, completionHandler: {
print("played sum")
self.bufferCount=0
})
a typical multi-channel PCM buffer has the channels interleaving on a per sample basis although, not being familiar with swift audio, I find it refreshing to see here channels given a dimension on the buffer datastructure
... a flag goes up when I see your guard checks clamping val > 1 set to val = 1 etc. ... elsewhere that is not needed as those boundary checks are moot as the data nicely falls into place as is
... my guess is your input audio[] is signed int 16 because of your val > 1 and val < -1 ? if true then dividing by max int float is wrong as you would be loosing half your dynamic range ...
I suggest you look closely at your
var val = Float( Int16(audio[i]) ) / Float(Int16.max)
lets examine range of your ints in audio[]
2^16 == 65536 // if unsigned then values range from 0 to (2^16 - 1) which is 0 to 65535
2^15 == 32768 // if signed then values would range from -32768 to (2^15 - 1) which is -32768 to 32767
Please tell is whether input buffer audio[] is signed or not ... sometimes its helpful to identify the max_seen and min_seen values of your input data ... do this and tell us the value of max and min of your input audio[]
Now lets focus on your desired output buffer self.buffer.floatChannelData ... since you are saying its 16 bit float ... what is the valid range here ? -1 < valid_value < 1 ?
We can continue once you tell us answers to these basic questions
I am a student in high school and I am currently learning in Delphi XE3. We are learning about BIT manipulation. We have an assignment and while I have read a lot on the subject and understand the entire process of storing information in Bits and SHL/SHR I am having difficulty understanding how to do this process in Delphi.
The assignment is as follows:
Decimal Hexidecimal Binary
1 0x0001 0000000000000001
2 0x0002 0000000000000010
4 0x0004 0000000000000100
Passing an integer value in an XML file to identify the options set. For example. If I wanted to send option 1 and option 2, I would add 1+2=3. I would send 3 as the number to specify that options 1 and 2 are true.
On the client the binary value would be 0000000000000011 = 3
From what I have read I need to use a mask but I do not understand how to do this. How would do I use masks in Delphi ot obtain the individual values which would be True or False.
I tried doing this in a regular Integer variable but it always gets treated as an Integer and the result is very strange. If I convert the integer to a binary string representation and I iterate thru the characters the result is correct but I am assuming that I should not be doing this with strings. Any help or an example would be greatly appreciated. Thank you.
You usually check if a particular bit is set in a Integer variable using the and binary operator, and you set individual bits using the or operator, like this:
const
OPTION_X = $01;
OPTION_Y = $02;
OPTION_Z = $04;
var
Options: Byte;
begin
Options := OPTION_X or OPTION_Y; //actually 3, like in your example
//check if option_X is set
if (Options and OPTION_X) = OPTION_X then
ShowMessage('Option X is set'); //this message is shown, because the bit is set
//check if option_Z is set
if (Options and OPTION_Z) = OPTION_Z then
ShowMessage('Option Z is set'); //this message is NOT shown
end;
The different OPTION_ constants, are actually masks, in the sense they are used to mask bits to zero (to check if a particular bit is set) or to mask bits to 1 (to set a particular bit).
Consider this fragment:
begin
..
if cbOptionX.Checked then
Options := Options or OPTION_X;
..
the or will mask the first bit to 1. If we start with a Options value (in binary) of 01010000, the resulting Options would be 01010001
01010000
OR 00000001 //OPTION_X
= 01010001
the same value is used to mask all the other bits to 0 to check if a particular bit is set. The if condition, for example: (Options and OPTION_Z) = OPTION_Z, does this:
first it MASKS all the non-interesting bytes of the Option variable to 0. If we consider the last value of 01010001, the operation will result in clearing all the bits, but the first.
01010001
AND 00000001
= 00000001
considering a starting value of 01010000 it will return zero:
01010000
AND 00000001
= 00000000
next, it compares if that value is equal to the mask itself. If it is equal, the bit was set in the original Options variable, otherwise it was not set. If your mask contains only one bit, that's matter of taste, you can just check if the resulting value is, for example, different than 0, but if your mask contains multiple bits and you want to check if all the bits was set, you have to check for equality.
Delphi has a predefined type TIntegerSet which allows to use set operators. Assuming that options is an Integer, you can check if any bit (0-based) is set like this:
option1 := 0 in TIntegerSet(options); { Bit 0 is set? }
option3 := 2 in TIntegerSet(options); { Bit 2 is set? }
Changing the options is done via Include or Exclude:
Include(TIntegerSet(options), 0); { set bit 0 }
Exclude(TIntegerSet(options), 2); { reset bit 2 }
Of course you can use any other set operator that may be helpful.
Delphi has Bitwise Operators for manipulating individual bits of integer types. Look at the shl, shr, and, or, and xor operators. To combine bits, use the or operator. To test for bits, use the and operator. For example, assuming these constants:
const
Option1 = 0x0001;
Option2 = 0x0002;
Option3 = 0x0004;
The or operator looks at the bits of both input values and produces an output value that has a 1 bit in places where either input value has a 1 bit. So combining bits would look like this:
var
Value: Integer;
begin
Value := Option1 or Option2;
{
00000000000000000000000000000001 Option1
00000000000000000000000000000010 Option2
-------------------------------- OR
00000000000000000000000000000011 Result
}
...
end;
The and operator looks at the bits of both input values and produces an output value that has a 1 bit only in places where both input value have a 1 bit, otherwise it produces a 0 bit instead. So testing for bits would look like this:
var
Value: Integer;
Option1Set: Boolean;
Option2Set: Boolean;
Option3Set: Boolean;
begin
Value := 7; // Option1 or Option2 or Option3
Option1Set := (Value and Option1) = Option1;
{
00000000000000000000000000000111 Value
00000000000000000000000000000001 Option1
-------------------------------- AND
00000000000000000000000000000001 Result
}
Option2Set := (Value and Option2) = Option2;
{
00000000000000000000000000000111 Value
00000000000000000000000000000010 Option2
-------------------------------- AND
00000000000000000000000000000010 Result
}
Option3Set := (Value and Option3) = Option3;
{
00000000000000000000000000000111 Value
00000000000000000000000000000100 Option3
-------------------------------- AND
00000000000000000000000000000100 Result
}
...
end;